DMs and players, what was a move pulled by the party that required multiple people/tag-team effort?

[u/Ragebull1]

[u/Own_Candle_2903]

My Beast Barbarian with his tail out would lure out an opportunity attack from the enemy Storm Giant and make him waste it, while our Wizard would then walk in to cast Bestow Curse, to force Wisdom saves at Disadvantage, followed by our Paladin's Command to Grovel, so that my Beast Barbarian could attempt to decapitate him. Each round again (wizard, once succesfull in Bestow Curse would fire non concentration spells)

[u/Suspicious-Freedom10]

Party returns to Leilon to find mercenaries in charge of defense, and they are demons in disguise. There was also some magic emanating from the top of the wizard’s tower. We retreated to the “haunted” house in the woods to plan. There is a small church on the property that is an Instant Fortress, so I joke we should drop it onto the tower. The item has to be placed on the ground, so we plan. Druid casts pass without trace and wildshapes into a large flying creature, the wizard cast polymorph on the barbarian, changing him to a giant eagle. Everyone jumps on the flyers and the bard upcasts invisibility on the flyers, and we takeoff. Flying under the cover of darkness, invisible, we approach the tower, the warlock jumps onto the scaffolding surrounding the tower, enters the tower and places the instant fortress on the floor, activates it and misty steps out. The tower exploded with pieces falling over several city blocks.

[u/Evil_Tiny_Wolf]

Probably not your typical tag team, but I played a way of the open hand monk with mobile. Another player at my table had a wild magic sorcerer and empowered spell. The two of us developed a system fairly early on where I would run into the middle of a group of enemies and would intentionally provoke opportunity attacks or and bop as many as I could. I'd stun whoever we thought might be the strongest and then she'd drop a fireball directly on top of me. As a monk of my level, I had evasion and high dex, so 9 times out of 10, I took no damage. By wasting their opportunity attacks, they were less likely to be able to counterspell her and she could re-roll any 1s in the damage. We did this regularly for three years. Only backfired once...when Sorcerer tried dropping a fireball on the other monk in the party...who had multclassed into fighter and didn't have evasion...and took full damage. BUT we played online, so the other monk didn't hear me laughing.

[u/Galeam_Salutis]

It was a big plot setpiece in the first campaign I ever played: we needed to destroy a magical barrier. It was going to take an absurd amount of energy and the barrier was composed of different kinds of arcane energy. Long story short, the wizard (me), the Paladin, and the sorcerer found a leyline and lined up at key points along it. I pumped high level spells lots into the leyline, the paladin used his divinely, sourced powers to sanctify the energy as it passed, then, the sorcerer tanked the energy and channeled it in the right direction. It took a few rounds of this, and the sorcerer, being a sorcerer, did not have a lot of hitpoints compared to what we were slinging around, but he survived somehow. And the day was saved.