My homebrew world has tabaxi featured rather prominently as one of the most widespread "mutant" races that arose from former dumb animals after the cataclysm that left dangerous radiation all over the world. There are three distinct varieties, two based obviously on lions and cheetahs, and the third (the one actually called "tabaxi") actually being the most "civilized" in the sense other races mean it. The first two types are typically primitive tribal people living in the wilderness, like the original tabaxi of D&D, but my version of the "main" race is a radical departure from that take.
I played up the housecat angle, really, and made the race's single most defining characteristic (aside from their great DEX) their curiosity. They're eager to learn new things, they're the only race besides humans that gets extra skill points each level (though in tabaxi's case the rules mandate that they have to spend the extra skill points on cross-class skills if possible). Their favored class is Bard, the only race in my world that has that (I kept the Gnomes as Illusionists or other varieties of mage depending on subrace). Culturally they're known as incredible gossips, always telling tales and swapping stories- and tabaxi spymasters are second to none. If I ever run an intrigue game in this world, tabaxi will almost certainly be the most popular racial choice besides human. Aside from that, they remained arboreal by preference, they're usually allies of the elves, and they commonly live in towns and cities in their own districts because other people rarely have the patience to deal with their constant chattering.
I don't have any "main race" tabaxi in my game as PCs ATM, but I do have a leonal (the lion-variant) as one of the "core" members of the epic-level party. She's been with the group since about 8th level, and has been that party's main blaster-mage (she's a sorceress who recently multiclassed to favored soul of the Nature goddess and then to mystic theurge) for most of the campaign. In the game plot she was thought to be the last survivor of a doomed tribe, a chief's daughter who managed to hide and flee long enough to get revenge on those who destroyed her tribe, but since hitting epic she's learned that she's not the only survivor of her tribe, gathered the survivors together under her banner and found a new homeland for them, and recovered an artifact of her race which will be used in battle against a coming apocalyptic event that threatens the entire world.