Is your 5e combat too fast and simple? Too seamless? Add some complication with teamwork benefits!
This is a revised version of an earlier blog post. Some of these are pretty good, so you might want to only use them if your party is not very optimized or in conjunction with a slightly upped game difficulty.
Total the party’s intelligence modifiers, plus the charisma modifier of the character with the highest charisma (the de facto party leader). The points are then spent by unanimous consent on up to three of the following benefits that help the entire party:
Plan (2): The party has a +2 bonus to initiative.
Master Plan (3): The party has a +4 bonus to initiative. It's up to you whether this stacks with Plan (I'd lean toward not).
Preventative Medicine (3): Players’ healing spells and potions that restore hp each heal an additional +1 hp.
Over The Top (4): Players have +15 feet (3 spaces) to their movement speed during the first round of combat.
Seize The Advantage (5): Any time an enemy provokes attacks of opportunity from at least one player, they suffer 1 damage per adjacent player. This happens before any attacks are made.
Alarum (6): The minimum initiative roll of any player is 6.
Back To Back (6): Players have +1 AC and +1 to saves while adjacent to at least one other player.
Fancy Footwork (7): At the start of each player’s turn, they may swap spaces with a single adjacent ally at no cost to their movement.
No Adventurer Left Behind (8): Prone players that are adjacent to at least one standing ally can stand up by spending only 5 feet of their movement, rather than half their maximum (PHB p191).
Tag-Team (9): You have +2 to attack flanked creatures. I know this is a throwback mechanic in the context of 5e, but I totally don’t care.
Blitz (10): Players have advantage with melee attacks during the first round of combat.
Opening Volley (11): Players have advantage on ranged attacks during the first round of combat.
Encircle (12): Players have advantage with melee attacks against foes adjacent to at least four players.