Besides the obvious so called "weapon platforms" I think my fav specific combo is Trinity with a gas paris prime incarnon. Gas can't do much against armour and Trinity has an armour strip on her link. The problem is the link strips only 3 enemy so regular aoe weapons (that can't kill armoured enemies) are able to kill only 3 enemies per shot. Yet the gas clouds persist after the shot so you have that satisfying chain reaction of sorts.
Is that the best build I've ever played? Not really. Can I do half an hour sp survival using it? I sure can and it's almost chill (except ridiculously short duration of Trinity's abilities).
As to the weapon platforms - I quite like nourish wisp, can slap any decent weapon and it'll become a lot better, roar hildryn is just absurd with full strip and double damage from roar.
Kuva Ayuanga (or whatever it's called) because I didn't notice you can preview which weapon a Lich will have before you spawn it and my first Lich had it.