What are some of your favourite interactions in the game?
They could be a champ v champ combination, specific nodes, anything. But say why, you never know when someone might read these and realise "wow, I never thought of that!"
Some of mine are:
Doom v Hela - get her in the corner and then just Doom-Slap forever because the knock-down triggers a physical resistance buff, which is immediately staggered, causing a shock, allowing another stun-slap - repeat ad infinitum.
Omega Red v Biohazard node - you're immune to the poisons, and the Bleeds only make you stronger, it's the best way to use OR without having Recoil masteries on yourself.
My latest favourite: Wiccan v Gorr. Get the neutralise onto him and keep it active - then every time you hit him he tries to proc buffs, only to have them neutralised and causing more incinerates - then just watch him burn!