The other day, I sat down at a table where I was the only "mono-class". The leader of the group, was a Charisma caster, wearing heavy armor, casting cure wounds and adding her Charisma modifier plus Disciple of Life because of one level of Cleric. She was also casting Eldritch Blast in Melee because of Crossbow Expert and two levels of Warlock. In the end, I think she was a Cleric 1/Warlock 2/ Bard 2 but she ran Shield of Faith once per short rest with Pact Magic. The Tank of the group had a level of Fighter with the Defense Style, two levels of Warlock again coupled with Crossbow mastery for the Melee 1d10+Cha, and he had at least one level of Sorcerer because he was casting Shield once or twice per short rest with Pact Magic for an amazing AC 25 in Splint. The Striker must have been a Paladin 3/Warlock 2 with Polearm Master, since he would open with a Thunderous Smite+Divine smite and follow-up with Halberd multi-attack. He also used Pact Magic to cast Shield of Faith and cast False Life at-will.
So, I thought I would try my hand at a silly-multi-class-cheese-weasel, by borrowing Defense Style from Fighter, Shield of Faith from Cleric and Shield from Sorcerer for AC 26 in Chain Mail.