Our launcher protocol document is woefully out of date, but below are all the cvars marked CVAR_SERVERINFO, which are the ones that get sent. Note also that for the time being those with a value of empty or 0 are not sent.
This list reflects 0.7.0 and is subject to change in upcoming versions:
co_fineautoaim
co_zdoomsoundcurve
co_zdoomswitches
co_zdoomphys
co_boomsectortouch
co_boomlinecheck
co_allowdropoff
co_blockmapfix
co_fixzerotags
co_fixweaponimpacts
co_nosilentspawns
co_realactorheight
co_level8soundfeature
sv_gametype
sv_hostname
sv_website
sv_email
sv_motd
sv_waddownload
sv_maxclients
sv_maxplayers
sv_maxplayersperteam
sv_teamsinplay
sv_scorelimit
sv_fraglimit
sv_timelimit
sv_intermissionlimit
sv_unblockplayers
sv_spawndelaytime
sv_forcerespawntime
sv_forcerespawn
sv_weaponstay
sv_keepkeys
sv_infiniteammo
sv_unlag
sv_maxunlagtime
sv_ticbuffer
sv_skill
sv_itemsrespawn
sv_itemrespawntime
sv_doubleammo
sv_monstershealth
sv_nomonsters
sv_monstersrespawn
sv_monsterdamage
sv_fastmonsters
sv_allowtargetnames
sv_fragexitswitch
sv_forcewater
sv_weapondamage
sv_friendlyfire
sv_teamspawns
sv_freelook
sv_allowshowspawns
sv_allowwidescreen
sv_allowpwo
sv_allowredscreen
sv_allowmovebob
sv_allowjump
sv_allowexit
sv_allowcheats
sv_splashfactor
sv_aircontrol
sv_gravity
ctf_flagtimeout
ctf_flagathometoscore
ctf_manualreturn