User blog comment:RA2/Robot Wars Rankdown: Extreme 1 Discussion & Questions/@comment-2118191-20180605041214/@comment-2118191-20180605065553

Exclusive to Extreme 1 - Ajjay, Arnold A. Terminegger, The Spider, Killertron, Aggrobot 3, Comengetorix, Draven, Cerberus, Panzer Wraith, Cataclysmic Variabot, Shear Khan, Scorpion, Spirit of Knightmare, Judge Shred 2.5, Disc-O-Inferno and all the international and forces robots.

Exclusive to Extreme 2 - Typhoon 2, Saw Point (I don't see why it can't be considered different from A-Kill), Lambsy, Rick, Mini Morg, Velocirippa, Lightning, Nasty Humphrey, Diotoir, Pussycat, 2/3rds of the New Blood competitors, C.V., Bondi-Titch, Cerberus and the EC robots.

Exclusive to Nickelodeon - Phantasm, Zanzara, Ming 3, Rick, Bigger Brother, Hoot, Tut Tut, Vert-I-Go, Squirmin Vermin, Humdrum, Rigby, Hannibal, The Piecemaker.

I think that covers all the bases.