According to a NeoGAF user who studied the Titanfall Beta code for PC, many of the potential game modes, perks, ordinances and weapon classes of Titanfall have been revealed.

Given it is merely a beta it would be wrong to assume this list is current and correct and should therefore be treated as rumor and speculation.

Game modes:

AT – Attrition?
TDM – Team Deathmatch?
CTF – Capture the Flag?
LTS – Last Titan Standing?
HP- Hardpoint Capture?
VM – Variety Mode (a mix of all the other modes listed, sans campaign)

Titan/Pilot perks:

auto_eject – Auto Eject
build_up_nuclear_core – Nuclear Ejection
dash_recharge
dead_mans_trigger
defensive_core
doomed_time – Survivor
enhanced_titan_ai
fast_reload – Fast Autoloader
hyper_core
icepick
longer_bubble – Dome Shield Battery
marathon_core
minimap_ai – Minion Detector
ordnance_pack – Explosive Pack
power_cell – Power Cell
run_and_gun
shield_regen – Regen Booster
stealth_movement
titan_punch
turbo_drop – Warpfall Transmitter
wall_runner – Enhanced Parkour kit

Pilot and Titan ordinances:

arc_grenade
bubble_shield
cloak
cluster_rocket
frag_grenade
heal
homing_rockets
proximity_mine
satchel charge
salvo_rockets
shoulder_rockets
smoke
sonar
vortex

Weapon class names:

p2011
p2011sp
p2011_auto
w1128
r97
b3wing
rspn101_carbine
m1a1_hemlok
lmg_hemlok
g2a4
car101
rspn101
at_rifle
rspn101_dmr
SMR
satchel_charge
data_knife
titan_vortex_blocker
xotbr16
thr_40mm
caber_shot
proximity_detonator
frag_grenade
defender_charge
shoulder_rocket
sentry_turret
auto_rocket_launcher
titan_triple_threat
titan_sniper_rifle
titan_rocket_pod
titan_arc_rifle
titan_sniper_rifle
titan_shotgun

SOURCE: NeoGAF via Reddit