The rules are it has to be just a Rahi, no 2 packs; for example, Jaller and Gucko is disqualified because it has Jaller in it. For me it gotta be the Tarakava.
I vote Keetongu. 05 titans were among the best, He has a unique appearance, and the launcher built into the torso was a cool quirk
I share Wekua’s sentiment on Keetongu, he’s really unique and cool. The color that he introduced (bright light orange, aka keetorange) is one of my favorite Lego part colors. Plus, he gets bonus points for being a comparatively cheap set nowadays, I’ll probably pick him up sometime soon.
Beyond that I vote for Muaka and Kanera. I don’t own the set but recently had the chance to play around with it for a while, it’s really fun. The extending neck with snapping jaw mechanism is well executed and works great, and the gimmick off pulling out each other’s masks to disable the opponent is novel. Their combo model also looks imposing.
And while you said that the set doesn’t count, I should mention that Pewku’s legs are too fun!