Preferably excluding legendaries, as it obviously very easy to make a good team out of them.
A team I built for lower-levels Pokemon Stadium that did pretty well (got me a cup) was something like:
Raichu
Dratini
Arcanine
Gyarados
Mankey
I’m struggling to remember the last member, grass or even Butterfree, but there were multiple rounds so I may have switched. I recall one difficulty was the threat of both earthquake (which half the grasses are vulnerable to) and rock slide from grounds so at one point I experimented with Lapras to supplement Gyarados.
No lie I love Butterfree.