Commands of various types, probable in CS 1.5 are below resulted.
Some from them are applicable only in the certain modes of game.

_cl_autowepswitch
_snd_mixahead
addip
adjust_crosshair
alias
allow_spectators
ambient_fade
ambient_level
appenddemo
ati_npatch
ati_subdiv
autosave
banid
bgetmod
bgmbuffer
bgmvolume
bind
bitmapfonts
bottomcolor
brightness
buy
buyammo1
buyammo2
buyequip
c_maxdistance
c_maxpitch
c_maxyaw
c_mindistance
c_minpitch
c_minyaw
cam_command
cam_contain
cam_idealdist
cam_idealpitch
cam_idealyaw
cam_snapto
cancelselect
cd
cd close
cd eject
cd info
cd loop
cd mp3info
cd mp3track
cd off
cd on
cd pause
cd play
cd remap
cd reset
cd resume
cd stop
changelevel
changelevel2
chase_active
chase_back
chase_right
chase_up
chooseteam
cl_allowdownload
cl_allowupload
cl_anglespeedkey
cl_backspeed
cl_bob
cl_bobcycle
cl_bobup
cl_chasedist
cl_clockreset
cl_cmdbackup
cl_cmdrate
cl_corpsestay
cl_dlmax
cl_download_ingame
cl_dynamiccrosshair
cl_fixtimerate
cl_forwardspeed
cl_gaitestimation
cl_gg
cl_himodels
cl_idealpitchscale
cl_latency
cl_lc
cl_lw
cl_messages
cl_minmodels
cl_movespeedkey
cl_needinstanced
cl_nopred
cl_nosmooth
cl_observercrosshair
cl_pitchdown
cl_pitchspeed
cl_pitchup
cl_rate
cl_resend
cl_righthand
cl_showerror
cl_showevents
cl_showfps
cl_showmessages
cl_shownet
cl_sidespeed
cl_slist
cl_smoothtime
cl_solid_players
cl_timeout
cl_updaterate
cl_upspeed
cl_vsmoothing
cl_waterdist
cl_yawspeed
clear
clearplayers
clientport
cmd
cmdlist
com_filewarning
commentator
con_color
con_fastmode
con_notifytime
con_trace
condebug
condump
connect
console
contimes
coop
crosshair
cvarlist
d_mipcap
d_mipscale
d_spriteskip
d_subdiv16
deathmatch
decalfrequency
default_fov
delta_clear
delta_stats
demos
dev_overview
developer
direct
disconnect
displaysoundlist
dlfile
drawradar
drop
dropclient
echo
edgefriction
endmovie
entities
envmap
escape
ex_correct
ex_diminishextrap
ex_extrapmax
ex_interp
ex_maxaccel
ex_maxerrordistance
ex_maxspeed
ex_minvelocity
exec
exit
exit prompt
fakelag
fakeloss
fastsprites
firstperson
flush
fly
ForceCloseCommandMenu
fps_max
fps_modem
fullinfo
fullserverinfo
fullupdate
gamedir
gamma
getcertificate
gg
gl_affinemodels
gl_alphamin
gl_clear
gl_cull
gl_d3dflip
gl_dither
gl_dump
gl_flipmatrix
gl_keeptjunctions
gl_lightholes
gl_log
gl_max_size
gl_monolights
gl_nobind
gl_nocolors
gl_overbright
gl_palette_tex
gl_picmip
gl_playermip
gl_polyoffset
gl_reporttjunctions
gl_round_down
gl_spriteblend
gl_texels
gl_texturemode
gl_wateramp
gl_wireframe
gl_zmax
gl_ztrick
god
graphheight
gunsmoke
heartbeat
hideconsole
hideradar
hisound
host_framerate
host_killtime
host_limitlocal
host_profile
host_speeds
HostMap
hostname
hostport
hpk_maxsize
hpkextract
hpklist
hpkremove
hpkval
hud_capturemouse
hud_centerid
hud_classautokill
hud_deathnotice_time
hud_draw
hud_drawhistory_time
hud_fastswitch
hud_saytext
hud_saytext_time
hud_takesshots
impulse
interp
invnext
invprev
ip
ip_clientport
ip_hostport
ipx_clientport
ipx_hostport
joyadvanced
joyadvancedupdat
joyadvaxisr
joyadvaxisu
joyadvaxisv
joyadvaxisx
joyadvaxisy
joyadvaxisz
joyforwardsensitivity
joyforwardthreshold
joyname
joypitchsensitivity
joypitchthreshold
joysidesensitivity
joysidethreshold
joystick
joywwhack1
joywwhack2
joyyawsensitivity
joyyawthreshold
kick
kill
lambert
lastinv
lightgamma
list
listdemo
listen
listid
listip
load
loadas8bit
localinfo
log
logaddress
logsdir
lookspring
lookstrafe
lservercfgfile
m_filter
m_forward
m_pitch
m_side
m_yaw
map
mapcyclefile
maps
max_shells
max_smokepuffs
maxplayers
mcache
menuselect
messagemode
messagemode2
model
motdfile
mp_allowmonsters
mp_autokick
mp_autoteambalance
mp_buytime
mp_c4timer
mp_chattime
mp_consistency
mp_decals
mp_fadetoblack
mp_flashlight
mp_footsteps
mp_forcecamera
mp_forcechasecam
mp_fragsleft
mp_freezetime
mp_friendlyfire
mp_ghostfrequency
mp_hostagepenalty
mp_kickpercent
mp_limitteams
mp_logdetail
mp_logecho
mp_logfile
mp_logmessages
mp_mapvoteratio
mp_maxrounds
mp_mirrordamage
mp_playerid
mp_roundtime
mp_startmoney
mp_timeleft
mp_timelimit
mp_tkpunish
mp_winlimit
MP3Volume
multicastport
name
net_address
net_chokeloop
net_drawslider
net_graph
net_graphpos
net_graphwidth
net_log
net_scale
net_showdrop
net_showpackets
new
nightvision
noclip
nosound
notarget
password
path
pausable
pause
pb
ping
pingservers
play
playdemo
playvol
pointfile
port
precache
quit
quit prompt
r_aliastransadj
r_aliastransbase
r_ambient_b
r_ambient_g
r_ambient_r
r_bmodelhighfrac
r_bmodelinterp
r_cachestudio
r_cullsequencebox
r_decals
r_drawentities
r_drawflat
r_draworder
r_drawviewmodel
r_dspeeds
r_dynamic
r_fullbright
r_glowshellfreq
r_graphheight
r_lightmap
r_lightstyle
r_luminance
r_maxedges
r_maxsurfs
r_mirroralpha
r_mmx
r_norefresh
r_novis
r_numedges
r_numsurfs
r_polymodelstats
r_reportedgeout
r_reportsurfout
r_speeds
r_timegraph
r_traceglow
r_wadtextures
r_wateralpha
r_waterwarp
radio1
radio2
radio3
rate
rcon
rcon_address
rcon_password
rcon_port
receipt
reconnect
record
reload
removedemo
removeid
removeip
resetrcon
restart
retry
room_delay
room_dlylp
room_feedback
room_left
room_lp
room_mod
room_off
room_refl
room_rvblp
room_size
room_type
s_2dvolume
s_a3d
s_automax_distance
s_automin_distance
s_blipdir
s_bloat
s_buffersize
s_disable_a3d
s_distance
s_doppler
s_eax
s_enable_a3d
s_geometry
s_leafnum
s_materials
s_max_distance
s_min_distance
s_numpolys
s_occ_epsilon
s_occfactor
s_occlude
s_polykeep
s_polysize
s_refdelay
s_refgain
s_reflect
s_reverb
s_rolloff
s_show
s_showtossed
s_usepvs
s_verbwet
save
say
say_team
scr_centertime
scr_connectmsg
scr_connectmsg1
scr_connectmsg2
scr_conspeed
scr_ofsx
scr_ofsy
scr_ofsz
scr_printspeed
screenshot
sendents
sendres
sensitivity
servercfgfile
serverinfo
setdemoinfo
setinfo
setinfo _ah
setinfo _vgui_menus
setmaster
showbriefing
showinfo
showpause
shutdownserver
sizedown
sizeup
sk_12mm_bullet1
sk_12mm_bullet2
sk_12mm_bullet3
sk_9mm_bullet1
sk_9mm_bullet2
sk_9mm_bullet3
sk_9mmAR_bullet1
sk_9mmAR_bullet2
sk_9mmAR_bullet3
sk_agrunt_dmg_punch1
sk_agrunt_dmg_punch2
sk_agrunt_dmg_punch3
sk_agrunt_health1
sk_agrunt_health2
sk_agrunt_health3
sk_apache_health1
sk_apache_health2
sk_apache_health3
sk_barney_health1
sk_barney_health2
sk_barney_health3
sk_battery1
sk_battery2
sk_battery3
sk_bigmomma_dmg_blast1
sk_bigmomma_dmg_blast2
sk_bigmomma_dmg_blast3
sk_bigmomma_dmg_slash1
sk_bigmomma_dmg_slash2
sk_bigmomma_dmg_slash3
sk_bigmomma_health_factor1
sk_bigmomma_health_factor2
sk_bigmomma_health_factor3
sk_bigmomma_radius_blast1
sk_bigmomma_radius_blast2
sk_bigmomma_radius_blast3
sk_bullsquid_dmg_bite1
sk_bullsquid_dmg_bite2
sk_bullsquid_dmg_bite3
sk_bullsquid_dmg_spit1
sk_bullsquid_dmg_spit2
sk_bullsquid_dmg_spit3
sk_bullsquid_dmg_whip1
sk_bullsquid_dmg_whip2
sk_bullsquid_dmg_whip3
sk_bullsquid_health1
sk_bullsquid_health2
sk_bullsquid_health3
sk_controller_dmgball1
sk_controller_dmgball2
sk_controller_dmgball3
sk_controller_dmgzap1
sk_controller_dmgzap2
sk_controller_dmgzap3
sk_controller_health1
sk_controller_health2
sk_controller_health3
sk_controller_speedball1
sk_controller_speedball2
sk_controller_speedball3
sk_gargantua_dmg_fire1
sk_gargantua_dmg_fire2
sk_gargantua_dmg_fire3
sk_gargantua_dmg_slash1
sk_gargantua_dmg_slash2
sk_gargantua_dmg_slash3
sk_gargantua_dmg_stomp1
sk_gargantua_dmg_stomp2
sk_gargantua_dmg_stomp3
sk_gargantua_health1
sk_gargantua_health2
sk_gargantua_health3
sk_hassassin_health1
sk_hassassin_health2
sk_hassassin_health3
sk_headcrab_dmg_bite1
sk_headcrab_dmg_bite2
sk_headcrab_dmg_bite3
sk_headcrab_health1
sk_headcrab_health2
sk_headcrab_health3
sk_healthcharger1
sk_healthcharger2
sk_healthcharger3
sk_healthkit1
sk_healthkit2
sk_healthkit3
sk_hgrunt_gspeed1
sk_hgrunt_gspeed2
sk_hgrunt_gspeed3
sk_hgrunt_health1
sk_hgrunt_health2
sk_hgrunt_health3
sk_hgrunt_kick1
sk_hgrunt_kick2
sk_hgrunt_kick3
sk_hgrunt_pellets1
sk_hgrunt_pellets2
sk_hgrunt_pellets3
sk_hornet_dmg1
sk_hornet_dmg2
sk_hornet_dmg3
sk_houndeye_dmg_blast1
sk_houndeye_dmg_blast2
sk_houndeye_dmg_blast3
sk_houndeye_health1
sk_houndeye_health2
sk_houndeye_health3
sk_ichthyosaur_health1
sk_ichthyosaur_health2
sk_ichthyosaur_health3
sk_ichthyosaur_shake1
sk_ichthyosaur_shake2
sk_ichthyosaur_shake3
sk_islave_dmg_claw1
sk_islave_dmg_claw2
sk_islave_dmg_claw3
sk_islave_dmg_clawrake1
sk_islave_dmg_clawrake2
sk_islave_dmg_clawrake3
sk_islave_dmg_zap1
sk_islave_dmg_zap2
sk_islave_dmg_zap3
sk_islave_health1
sk_islave_health2
sk_islave_health3
sk_leech_dmg_bite1
sk_leech_dmg_bite2
sk_leech_dmg_bite3
sk_leech_health1
sk_leech_health2
sk_leech_health3
sk_miniturret_health1
sk_miniturret_health2
sk_miniturret_health3
sk_monster_arm1
sk_monster_arm2
sk_monster_arm3
sk_monster_chest1
sk_monster_chest2
sk_monster_chest3
sk_monster_head1
sk_monster_head2
sk_monster_head3
sk_monster_leg1
sk_monster_leg2
sk_monster_leg3
sk_monster_stomach1
sk_monster_stomach2
sk_monster_stomach3
sk_nihilanth_health1
sk_nihilanth_health2
sk_nihilanth_health3
sk_nihilanth_zap1
sk_nihilanth_zap2
sk_nihilanth_zap3
sk_player_arm1
sk_player_arm2
sk_player_arm3
sk_player_chest1
sk_player_chest2
sk_player_chest3
sk_player_head1
sk_player_head2
sk_player_head3
sk_player_leg1
sk_player_leg2
sk_player_leg3
sk_player_stomach1
sk_player_stomach2
sk_player_stomach3
sk_plr_357_bullet1
sk_plr_357_bullet2
sk_plr_357_bullet3
sk_plr_9mm_bullet1
sk_plr_9mm_bullet2
sk_plr_9mm_bullet3
sk_plr_9mmAR_bullet1
sk_plr_9mmAR_bullet2
sk_plr_9mmAR_bullet3
sk_plr_9mmAR_grenade1
sk_plr_9mmAR_grenade2
sk_plr_9mmAR_grenade3
sk_plr_buckshot1
sk_plr_buckshot2
sk_plr_buckshot3
sk_plr_crowbar1
sk_plr_crowbar2
sk_plr_crowbar3
sk_plr_egon_narrow1
sk_plr_egon_narrow2
sk_plr_egon_narrow3
sk_plr_egon_wide1
sk_plr_egon_wide2
sk_plr_egon_wide3
sk_plr_gauss1
sk_plr_gauss2
sk_plr_gauss3
sk_plr_hand_grenade1
sk_plr_hand_grenade2
sk_plr_hand_grenade3
sk_plr_rpg1
sk_plr_rpg2
sk_plr_rpg3
sk_plr_satchel1
sk_plr_satchel2
sk_plr_satchel3
sk_plr_tripmine1
sk_plr_tripmine2
sk_plr_tripmine3
sk_plr_xbow_bolt_client1
sk_plr_xbow_bolt_client2
sk_plr_xbow_bolt_client3
sk_plr_xbow_bolt_monster1
sk_plr_xbow_bolt_monster2
sk_plr_xbow_bolt_monster3
sk_scientist_heal1
sk_scientist_heal2
sk_scientist_heal3
sk_scientist_health1
sk_scientist_health2
sk_scientist_health3
sk_sentry_health1
sk_sentry_health2
sk_sentry_health3
sk_snark_dmg_bite1
sk_snark_dmg_bite2
sk_snark_dmg_bite3
sk_snark_dmg_pop1
sk_snark_dmg_pop2
sk_snark_dmg_pop3
sk_snark_health1
sk_snark_health2
sk_snark_health3
sk_suitcharger1
sk_suitcharger2
sk_suitcharger3
sk_turret_health1
sk_turret_health2
sk_turret_health3
sk_zombie_dmg_both_slash1
sk_zombie_dmg_both_slash2
sk_zombie_dmg_both_slash3
sk_zombie_dmg_one_slash1
sk_zombie_dmg_one_slash2
sk_zombie_dmg_one_slash3
sk_zombie_health1
sk_zombie_health2
sk_zombie_health3
skill
skin
slist
slot1
slot10
slot2
slot3
slot4
slot5
slot6
slot7
slot8
slot9
snapshot
snapto
snd_noextraupdate
snd_show
soundfade
soundinfo
soundlist
spawn
speak
spec_autodirector
spec_decal
spec_drawcone
spec_drawnames
spec_drawstatus
spec_help
spec_menu
spec_mode
spec_pip
special
spk
startdemos
startmovie
stat
status
stop
stopdemo
stopsound
stuffcmds
suitvolume
sv_accelerate
sv_aim
sv_airaccelerate
sv_airmove
sv_allowdownload
sv_allowupload
sv_alltalk
sv_bounce
sv_cheats
sv_clienttrace
sv_clipmode
sv_contact
sv_failuretime
sv_filterban
sv_friction
sv_gravity
sv_instancedbaseline
sv_lan
sv_logbans
sv_logrelay
sv_maxrate
sv_maxspeed
sv_maxunlag
sv_maxupdaterate
sv_maxvelocity
sv_minrate
sv_minupdaterate
sv_newunit
sv_password
sv_proxies
sv_rcon_banpenalty
sv_rcon_maxfailures
sv_rcon_minfailures
sv_rcon_minfailuretime
sv_restart
sv_restartround
sv_send_logos
sv_send_resources
sv_skycolor_b
sv_skycolor_g
sv_skycolor_r
sv_skyname
sv_skyvec_x
sv_skyvec_y
sv_skyvec_z
sv_spectatormaxspeed
sv_stepsize
sv_stopspeed
sv_timeout
sv_unlag
sv_unlagpush
sv_unlagsamples
sv_visiblemaxplayers
sv_voicecodec
sv_voiceenable
sv_wateraccelerate
sv_wateramp
sv_waterfriction
sv_zmax
swapdemo
sys_ticrate
team
tell
texgamma
thirdperson
timedemo
timeleft
timerefresh
togglebrowser
toggleconsole
togglescores
topcolor
traceralpha
tracerblue
tracergreen
tracerlength
traceroffset
tracerred
tracerspeed
trackplayer
unbind
unbindall
upload
user
users
v_centermove
v_centerspeed
v_dark
version
vgui_emulatemouse
vid_d3d
vid_describemode
viewdemo
viewframe
viewmodel
viewnext
viewprev
viewsize
violence_ablood
violence_agibs
violence_hblood
violence_hgibs
voice_avggain
voice_clientdebug
voice_dsound
voice_eax
voice_enable
voice_fadeouttime
voice_forcemicrecord
voice_inputfromfile
voice_loopback
voice_maxgain
voice_modenable
voice_overdrive
voice_overdrivefadetime
voice_profile
voice_recordtofile
voice_scale
voice_serverdebug
voice_showbanned
voice_showchannels
voice_showincoming
volume
wait
waterroom_type
weapon_ak47
weapon_aug
weapon_awp
weapon_c4
weapon_deagle
weapon_elite
weapon_fiveseven
weapon_flashbang
weapon_g3sg1
weapon_glock18
weapon_hegrenade
weapon_knife
weapon_m249
weapon_m3
weapon_m4a1
weapon_mac10
weapon_mp5navy
weapon_p228
weapon_p90
weapon_scout
weapon_sg550
weapon_sg552
weapon_smokegrenade
weapon_tmp
weapon_ump45
weapon_usp
weapon_xm1014
writecfg
writeid
writeip
zoom_sensitivity_ratio
+alt1
+attack
+attack2
+back
+break
+camdistance
+camin
+cammousemove
+camout
+campitchdown
+campitchup
+camyawleft
+camyawright
+commandmenu
+duck
+forward
+graph
+jlook
+jump
+klook
+left
+lookdown
+lookup
+mlook
+movedown
+moveleft
+moveright
+moveup
+nvgadjust
+reload
+right
+score
+showscores
+speed
+strafe
+use
+voicerecord
-alt1
-attack
-attack2
-back
-break
-camdistance
-camin
-cammousemove
-camout
-campitchdown
-campitchup
-camyawleft
-camyawright
-commandmenu
-duck
-forward
-graph
-jlook
-jump
-klook
-left
-lookdown
-lookup
-mlook
-movedown
-moveleft
-moveright
-moveup
-nvgadjust
-reload
-right
-score
-showscores
-speed
-strafe
-use
-voicerecord

1023 commands in the list.

The author: cscentral