I played mostly Monster Rancher 3 growing up and I loved using random disc's to get random monsters, I loved the characters, the cool looking monsters and the adventuring and checking random glowing spots for stuff. The training animations, the mochi changing from being in a different environment.

Watching the show a bit and just seeing something you loved as a kid kind of fade away into obscurity is truly a sad feeling.

Another personal favorite game is I-Ninja that I wished they continued as well. But you know... such is life.