> Contrary + Simple, something like Superpower would raise your stats by two stages upon use, and something like Draco Meteor would basically be, use it twice and your SpA is +6
> Parental Bond + Skill Link, wouldn't this mean two five hit strikes in a row?
> Filter + Solid Rock, if they stack then you're cutting down damage taken by super effective hits by quite a bit
> Aerilate + Gale Wings, self explanatory
> Auto weather ability + Ability that works with said weather, set up a weather and immediately take advantage of it
> Mold Breaker + Infiltrator, no ability or Substitute can prevent you from mowing down your opponent
> Gooey + Effect Spore, not too OP but can really punish opponents with contact moves
> Iron Barbs + Rough Skin, and with a Rocky Helmet, that'll really punish opponents with contact moves
> Magic Bounce + Shield Dust, you repel status moves and you negate the added effect of opponent's regular attacks
> Skill Link + Technician, self explanatory
> Shadow Tag + Soundproof, sing Perish songs while your opponent is trapped and you're safe to sing, you just have to survive the next two turns
> a type absorbing move + another type absorbing move, like Motor Drive and Volt Absorb, self explanatory
> Natural Cure + Regenerator, never fear status and health drops less than 30%, just switch out and you'll be good as new
That's all I can think of for now. Some aren't too OP but it was fun to think about.