Some of my favorites that have a higher frequency of "major upset" events. It really depends on your group, and how they like to play.

I stick with pretty quick and accessible games, because we frequently have to teach new people and I hate spending 3 hours on one playthrough of a huge game and then the newbie never gets a chance to try again with their new understanding.

Favorites:

• Wizard reliably makes our whole table lose their minds
• Love Letter takes sudden drastic turns and is so quick to play
• Bang! (the dice version) has as much treachery as it does chaos
• No Thanks! is an exercise in collective sadism
• Nanuk has perhaps the best "oh shiiiiiiiiiiiii-" moments with a combination of hidden information, bluffing, push-your-luck, pleading for help, backstabbing, and high-stakes card flips

Bluffing games:

• Coup
• Skull
• Cockroach Poker

Card games with sudden win conditions:

• Five Crowns
• Mahjong
• LLAMA

Asymmetric information games:

• Secret Hitler
• Codenames
• Mysterium Park

Not as frequent, but sometimes perfect for the right crowd:

• Three Dragon Ante
• Get Bit!
• GUBS
• Ca$h n Guns has foam guns that the whole table points at each other at once, Mexican Stand-off style