Well, there's:
Kingdra - Quick with its T1/2 Donk, it's speed can deal nice damage for the whole game. A little reliant of Claydol, though.
AMU - With many various talents, AMU (The pixies) can deal powerful OHKOs, but are somewhat weak themselves.
Torterra/Scep - This 100 damage powerhouse is hard to KO and surprisingly rather easy to set up.
Leaf/Scep - An unlimited damage cap and accerlated attaching makes Leafy a powerful opponent.
Mag/Leaf - Power up Magmortar to OHKO your opponents quickly.
Rock Band (Beedrill swarm) - Get out four Beedrills to do 120 damage for one energy.
Belossom swarm - Same with Beedrill, but can be paired with the reactive Vileplume.
This is off the top of my head. There are a few more good ones. Have fun playing with them!