A Bug's Life for PS1 was by far my favorite, I've actually been wanting to revisit it. I remember getting the golden fruit in each level and annihilating the enemies. I also remember just how cool it felt to actually fly Flik across that little valley on the dandelion (or glide, whatever, you know what I mean). And then the epic level where you actually do fly with the princess, such a memorable game!
I also really enjoyed Hercules for PS1, but was a bit sad at it's lack of attempt of incorporating the story (my childhood self must have had such high expectations). But the game itself was super fun.
The last one I remember really enjoying was Donald Duck Going Quackers for the PS1. I wanted that game so bad, and then I just thought it was the greatest thing when I got it. It felt like an odd Disney try at the first Crash Bandicoot to me as a kid, and I had all the fun with it. I remember going back to all of the levels trying to unlock all of the bonus costumes and whatnot. I don't really know how this game would hold up today, but the memories are good.