* survival with friends (so-called SMPs)
* minigame type servers (Hypixel & friends)
* other servers (for example those that have completely custom game modes, although most of them are crappy because their owners have no idea what is going on)
* learn to make your own servers, learn Java if you're interested in that
* Learn Redstone
* Command blocks?
* Start making data packs
* Resource packs: Pixel Art, 3D modeling, Go outside and make a photorealistic resource pack, Sound Design, VFX, Parallax Occlusion Mapping, normal maps, specular maps, emissive textures, Custom Entity Models (yes, resource packs are not just made in paint.net)
* Skins
* Recreate something in the game
* Building
* Landscaping
* Make a perfect sphere and other useless stuff
* Play challenges e.g. beat Minecraft when you get a random effect every 30s. So, find a data pack on PMC or code your own like a champ.
* Speedrunning (different versions, categories)
* Mods although personally, I'm not into them
* Mapmaking (find the button that took 3 mins to make does not count)
* Just try to come up with interesting strategies - did you know you can place a block and light a fire on top of it, then shoot a bow through it for a homemade flame bow?
* Code custom features into the game (although that was kind of mentioned as mapmaking, server making and resource packs)
* Hardcore mc
* PVP
* Play some maps (good maps, like the Floo Network's Harry Potter Map)
* Make a shader pack
* Parkour
Most of these are insanely broad categories. The problem is, some think mc is just survival singleplayer.