Swords Dance + Screech (or similar combo)
Take just one turn to set up and do massive damage next turn. Especially good on bosses.
Protect + Disable
Trolls more powerful bosses and Pokemon, but isn't too good for long dungeons due to low PP.
Dragon Dance + any STAB Power Move OR High PP move
Good for mid size dungeons and bosses, take many Pokemon out fast and hard. I suggest the PP option unless specifically for bosses.
Healing Wish + Recover (or similar move)
pokemon like Cressilia post game are very good at this, but it is good to make sure they have decent AI skills and a good equipped item.
Light Screen + Reflect
sets up two turns worth of defense in one go, but isn't good for consumption purposes.
Magic Guard + Protect
I'll add more later. I might go and be a little more creative tomorrow or something on my game.