Lion-O: Shifter (razorclaw) Paladin
Panthro: Shifter (beasthide) Fighter/Expert
Tigra: Shifter ( ? ) Artificer
Cheetara: Shifter (longstride) ex-Barbarian/Monk
Wilykat/-kit: Shifter (cliffwalk) Rogues
Slithe: Tren (from Serpent Kingdoms) Fighter/Rogue
Monkian: Taer (from Unapproachable East) Barbarian
Jackalman: Jackalwere (possibly gnoll) Fighter
Vultureman: Aaracockra (Monsters of Faerun) Artificer
Mumm-ra: Mummy Cleric
I had only the vaguest thoughts on the three later Thundercats, but Lynxo is certainly a wildhunt monk.