I really enjoy Coup and The Resistance. Small box social deduction games.

6 Nimmt, just cards. Quick and fun.

The Gang - Coop poker. It's fun.

Just One - coop word game

Splendor can be played up to six with added tokens.

A larger game that is not too complicated and can play up to 8 (with expansions) is HEAT: Pedal to the metal. Very fun game.

I’d recommend:

• Ca$h n Guns: think reservoir dogs satire. silly, quick, fun, but know that you’ll be pointing orange foam handguns at everyone so may not work for all groups and settings
• Captain Sonar: I’ve only played it with exactly eight, but I loved every minute of it. I really liked how involved I got in doing my tasks, it feels intense and hectic, but is quick to teach and play
• Not Alone: plays up to 7 people, one versus everyone else. Intense and quick, I don’t think that I’ve ever had anyone not want to play another game after the first
• Happy Salmon: play and teach in something like 90 seconds. This game will never be a” main course” and there is the risk of losing your voice from shouting and laughing so much, but it’s great to get everyone in a good mood. You should 100% get a copy (or two so that you can play up to 12 people). Note that I’ve only played the original from North Star, but I’d be surprised if the new Exploding Kittens edition isn’t awesome as well.
• Codenames: There are about a million variants of this, plays well with big groups, but your mileage may vary depending on how well everyone knows each other (knowing your audience is key to making good clues)

I’m sure there are plenty that I’m missing (especially on the social deduction side of things), but those are some of my favorites.

Monikers would be a good addition by the sound of it

Cockroach poker comes to mind as well.

Another quick game for lots of people that can be played with just a deck of cards is In vino morte

Others of the top of my head:

• Anomia
• love letter (4 players)
• spot it
• roll for it
• dungeon drop

If you like Cards Against Humanity, Joking Hazard is a must.

Rock Paper Wizard is a fun party strategy game that’s easy to learn.

The Great Dalmuti is a classic that can also be rigged up with three decks of cards and some funny hats.

Some of my best party gaming when I was younger came from inheriting and seeding a new lineage of Mao like a party game sourdough starter.

I can recommend Sushi Go Party! It's the most played game in my collection and is a favourite across different groups of friends. It's easy to learn, doesn't take long and has good replay value. It works for 2-8 players. My only complaint is that I'm not a big fan of the original box insert, I've 3d printed a basic insert that works much better to keep the cards organised.

We have the same business “group”:

• Hellapagos: For 6 to 12 players. We made a 12 players game, it was a blast.
• Faraway is quiet smooth. I recommend 6 players max, needs 2 games with new players and I suggest to make a tiny pause between games.
• Skull & Roses for bluffing only.
• Bohnanza is a great fast tiny game. 6 is maybe too much.
• Metro X. A Roll and Write is always good for 6+ players. They are many of them available.
• Quatermaster General games are often very good at 6 players.

Sparkle Kitty is great. At first glance, you might think it is a game for little girls learning to read. Don't underestimate the fun of yelling silly phrases at each other. If you want to make it more competitive, you can play with the optional rules in the rule book.