Dot Hacks 1 through 3, the original PS2 series. I still haven't found 4, though the only searching I really do for it is scanning the PS2 section of a GameStop whenever I happen to stop by one. What I have found, though, is how hard it is to find used copies that still have the additional anime discs intact.
Also the original Catz and Dogz series. You know, the ones from the 90s and early 2000s for the PC, before they remade them into cheesy, shitty animal RPGs. (And before you say "But that's what they were before, too," I'd just like to mention that before you were raising the cats and dogs. In the remakes, you "are" the cat or dog, doing things like beating up a giant wolf who's taking over the world with the hat he stole from your dad).