First of all, I only tallied the robots seen in season three combat. I did this for a couple of reasons. One, I didn't feel like looking up the names of the robots that appeared in season two. It also means that I don't have to squint at shots of the pits to see what robots I can make out. So unless the robots are in the Treasure Island arena and are battling, I don't count them.

This list is divided up into three sections:

If a robot had one or more of its fights shown in full, then I place it in the first section. This section simply lists every robot in a featured fight, with the episode the fight(s) aired in following the name, in parentheses.

If a robot did not have any of its fights aired in full, but was shown and named (usually in the "Update" part of the show), then I place it in the second section. Again, the episode(s) it's mentioned in can be found in parentheses.

If a robot didn't even get its name mentioned on the air, but its image still was shown while it was fighting, then I place it in the third section. In addition to the episode number, I give a brief description of where it can be seen.

A huge thanks to robotcombat.com for cataloguing all the competitors so I could identify them and spell their names correctly.

So here's the list, preceded by one of those ruled lines that I seem to enjoy inserting in every page I've made lately:

NON-REGULATED (2 fights total)
ChinKilla (4, 7)
Ginsu (7)
LaMachine (7)

SUPER HEAVYWEIGHT (13 fights total)
Cuad the Crusher (3)
Dawn of Destruction (6)
Diesector (6, 7, 9)
Dreadnought (7)
Electric Lunch (8)
Hammertime (2)
The Judge (5)
Minion (1, 8, 9, 9)
Ogre (1)
Phere (7)
Rammstein (5, 7)
Techno Destructo (3, 7)
Toro (1, 7, 9)
Vladiator (2, 7, 9, 9)
World Peace (1)

HEAVYWEIGHT (18 fights total)
Bacchus (5)
BattleRat (3)
BioHazard (3, 7, 8, 8)
Crash Test Dummy (3)
Fork-N-Stein (2)
Gammatron (2)
Golddigger (5)
Greenspan (5)
Hexadecimator (2, 8, 8)
I-Beam (5)
KillerHurtz (4, 8)
Little Sister (2, 3)
MechaVore (3, 8)
M.O.E. (5)
Nightmare (1, 4)
Omega-13 (4)
Overkill (5, 8)
Reactore (4)
Slam Job (1)
Son of Whyachi (4, 8, 8, 8)
Tazbot (5, 7)
Vlad the Impaler (3)
Voltronic (5)

MIDDLEWEIGHT (13 fights total)
Ankle Biter (4)
Bad Attitude (2)
Blade Runner (3)
Complete Control (2)
Deadblow (5)
Double Agent (1, 6)
F5 (4)
Gungnire (4)
Hazard (6, 10, 10)
Little Drummer Boy (3, 10, 10)
Mordicus (4)
Nibbler (4)
SABotage (6, 10)
Something Must Die (4)
Subject to Change without Reason (2)
Sunshine Lollibot (6)
T-Minus (6, 9)
Turbo (1)
Twin Paradox (5)
T-Wrex (2, 9, 10)
Zion (6)

LIGHTWEIGHT (15 fights total)
Blood Moon (4, 6)
Carnage Raptor (4)
Death by Monkeys (5)
Dr. Inferno Jr. (2, 9, 10, 10)
Gamma Raptor (9, 10, 10)
General Gau (4)
HammerHead (4)
Herr Gepoünden (9)
Mouser Super Mecha-Catbot (6, 9)
Rim Tin Tin (4)
Sallad (4)
Shaft (4)
Shish-ka-bot 1.1 (1)
Shrike (7)
Sisyphus (5)
Toe Crusher (2)
Trilobot (1)
Wacker (3)
The Wacky Compass (6)
Wedge of Doom (6, 10)
Ziggo (3, 7)

SUPER HEAVYWEIGHT
Anubis (2, 7)
Atomic Wedgie (7)
DooAll (2)
Eradicator (4)
Gray Matter (4)
Half-Gassed (4)
Hoobot (1)
The Junkyard Cog (1)
No Apologies (5)
Odin II (7)
Revision Z (4, 5, 7)
Ronin (2)
Scrap Daddy Turbulence (1)
Tortoise (1)
Whyachi (1)

HEAVYWEIGHT
Bad Dog (4)
Bender (4)
B.O.B. (4)
Center Punch (4)
ChewBot (3)
Crab Meat (1, 4, 8)
Dreadbot (2)
frenZy (6)
FrostBite (8)
Gang Green Weasel (1)
The Heart of Darkness (4)
Icky Thump (3)
Incoming (7, 8)
Junkyard Offspring (3)
KillerB (2)
Kill-O-Amp (4, 8)
Kritical Mass 2 (3)
Mauler 51-50 (2)
Mjollnir (4)
Punjar (4)
RoboSapien (6, 8)
Shark Byte (1, 4, 8)
Surgeon General (4, 6)
Towering Inferno (4, 6)
Tripulta Raptor (2)

MIDDLEWEIGHT
BumperBawt (1)
Chiabot (3)
Eraser (8, 9, 10)
Fusion (6)
Garm (2)
Huggy Bear (2)
Instigator (2)
Scrap Daddy's Flipskanker (2)
Spinster (5)
Thwak (1)
Village Idiot (3, 8)

LIGHTWEIGHT
The Archduke (5)
Backlash (5, 6, 10)
Bad Habit (5)
Blood Dragon (1)
Fang (3)
Manic Aggressive (3)
Mantis (3)
Matts Bammer (3, 5)
Mecha Tentoumushi (5, 6)
No Tolerance III (6)
Rhode Hog (3)
Scrap Daddy Surplus (1)
Serial Box Killer (7, 9)
Skid Mark (3, 6, 7)
SnowFlake (9)
Sparky (3)
Sublime (7)
Whirligig (7)

HEAVYWEIGHT
Blendo (5: shown in prologue fighting Bacchus)
Scrap Daddy's Persistor (5: briefly seen fighting Golddigger at start of second half)

MIDDLEWEIGHT
Alabama Slammer (1: fighting Sunshine Lollibot in "bots to watch" segment)
Bouncing Betty (3: fighting Little Drummer Boy in segment about Little Drummer Boy)

LIGHTWEIGHT
Green Dragon (10: fighting Death by Monkeys in Lightweight Rookie of the Year segment)
Patriot (1: hit by killsaws in Pete segment)
Recycler (1: in scene while Whirligig thrown by saws in Pete segment)
Spin Reaper (7: pecked by Shrike in prologue)
Whirl Wep X25 (1: next to some killsaws in Pete segment)