Our go-tos are as follows!

• Monikers: A silly little game that turns from describing a word on the card into bizarre charades. It’s ALWAYS been a hit.
• 6 Nimmt!: Can play up to 10 and I’ve NEVER seen people get so turned up about slapping down a card with a number on it.

I really like 7 Wonders, for 3-7 players and one round is also not too long with about 20 minutes ^^

Deception - Murder in Hongkong - for up to 12 people

A good question and an interesting thread. At five, our group sometimes tries a substantial game like Viticulture or Power Grid. Knowing the game is critical, however, since many complex games are not at their best with five players. When our group hits six, we’ve recently been playing Mysterium, which is an excellent, simple investigation game with evocative art and a great deal of replay value. It’s surprisingly accessible for new players.

With even larger groups, we sometimes play Mascarade. This Bruno Faidutti social deduction game is similar to his later Citadels, but easier to get started with. Another hit has been Bohnanza, although its wheeling-and-dealing style may not appeal to quieter folks.

When we have players who are easily overwhelmed by lots of rules, we tend to fall back to Sushi Go. This is entertaining enough–though beware of playing it with hate-drafting Magic players.

EDIT: It’s “Mascarade”, not “Masquerade”.

• Fluxx

• Codenames

• Munchkin

• and if you’ll believe it, most people haven’t played in so long that it is usually a huge hit: Scattergories

I love light party games with a huge crowd.

For larger groups, we’ve had success with these:

Diamant

Bang:The dice game

Citadels

Skull

CamelUp

Just One

Fake artist goes to New York

Sushi Go:Party

Ethnos - area control/ set collection/ push your luck with very short turns; hard to get to the table with my group because of the art, but once we play, everyone liked it so far

Cosmic Encounter - classic game with a lot of diplomacy

https://boardgamegeek.com/boardgame/18/roborally - chaos & mayhem, aka. a lot of fun; can drag a bit if players don’t get the mechanics

Scythe has an expansion that goes to 6 or 7, I think. Some versions of Smallworld may as well. Formula D plays 10. Dixit can go high too if you have enough cards.

For 8-12 players, I like Green Team Wins.

At 6 players we mostly switch to party games.

• Just One is by far our favorite, works great with all sort of crowds.

• Secret Hitler is another we tend to play, doesn’t work well with the more casual folks.

Always interested in expanding this list, it’s hard to find something outside word games and social deduction that don’t have a ton of downtime.

We default to Munchkin when nothing else seems obvious. Games get long with 7 or more people because someone can always sabotage the leaders victory. But the game is still hilarious and gleefully fun to us after all these years.

These are my go to games for larger groups:

• Codenames: A modern classic! Works best with 6 or 8 people.
• Decrypto: For a more gamey version of Codenames.
• Wavelength: Fun party game that spikes interesting conversations
• Concept: Don’t play to win, just play to have fun guessing

Mysterium - identify the suspect by looking at abstract cards given by a ghost (goes up to 7 players I think; use the original Ukrainian rules!)
Shikoku - interesting movement game, goes up to eight players
Eclipse - epic space exploration and battles, nine players with the expansion (I’ve never played it nine players, it would probably take about a week and need a banqueting table to put it on)

Cash n Guns - 8 players: Players get to have a standoff with foam guns pointed at one another trying to take out each other either with a loaded gun or bluffing that your gun is loaded to gain the most loot that was gathered from a prior heist.

Wingspan can scale up to 6 or 7 players.

Werewolf is fun for even more.