Survival: The standard Minecraft experience where players gather resources, build, and survive, often with specific rules against "griefing" (destroying others' work).
Creative: Focuses entirely on building; players typically have infinite resources and the ability to fly.
Anarchy: Servers with no rules. Players can cheat, hack, and destroy anything they find. The most famous example is 2b2t.
Factions: A competitive survival mode where players form teams (factions), claim land, and go to war with others.
Minigames: Large hubs featuring short games like BedWars, SkyWars, or Spleef. Hypixel is currently the largest server of this type.
Skyblock/One Block: Players start on a tiny floating island with limited resources and must expand it to survive.