Best team up abilities

One thing not a lot of people talk about that I think sets this game apart from alot of other hero shooter games is the team up abilities.

It creates a whole new world of possibilities for team comps and synergies. I feel like the team up abilities are undervalued at the moment for obvious reasons as people just want to play the hero they like the most and are new to the game.

I feel like if the comp scene for this game takes off teams will be composed based off certain team up abilities.

What would you guys say are the best team up abilities in the game right now? I feel like the punisher infinite ammo with rocket racoon is really valuable.