Pokemon Stadium
LeachSeed, Toxic:
On Pokemon Stadium, if used LeachSeed and Toxic together in a combination, the foe becomes "Badly Seeded, and Poisoned!"
The Hp recovery will be 3 times the normal recovery!

FocusEnergy:
If you used Focus Energy, you may have noticed that your move have always landed a Critical hit!
If you combind that with PinMissile, you could KO Mewtwo with one shot!

Toxic, FireSpin/Wrap/Bind:
We all know what Toxic is capable of, but if you use it in a combination with FireSpin, Wrap, or, Bind, The Toxic will sap away the foe's Hp, and in the mean time, the foe cannot attack.
The foe could switch out, but you could continue to work this combo on the newly switched Pokemon!

Also works on Red, Blue And Yellow Versions
Thunderwave/StunSpore/Agility, FireSpin/Wrap/Bind:
For your first move, Thunderwave,StunSpore, or Agility, next, Use Wrap, Bind, or FireSpin.
As long as you're faster than the opponent, the foe could never fight back!
Your opponent's only hope, will be for you to miss, and that's not very often.

SwordsDance, HyperBeam:
first you use SwordsDance, then you use Hyperbeam.
As long as you manage to K.O. the Opponent, you don't need to recharge.

Pokemon Stadium 2
Encore, Disable:
First you Encore, then you Disable the Encored move!
the opponent will do absolutely nothing for about 5 turns!