If you're looking for something to do in your world besides beat bosses and level up here are some build ideas.
Armory: armor and weapons organized by each biome they are used in/ come from primarily. Probably a good idea to build this close to your house just in case.
Kitchen: A place to have all cooking and food storage, as well as a fancy room to store individual ingredients!
Harbor: Having ships is an important part of Valheim so having a harbor with docks and a repair/ storage building could be helpful in the long run. (personally, I've found needing a place to repair my ships helpful)
Watch towers: When your base gets raided by trolls or drauger having a place to shoot enemies from up high by your base can help out and minimize damage to other areas of your home. Though I would recommend building a watch tower out of stone, wood is too fragile.
Farmhouse: because food is one of the most important parts of Valheim having a place where you can breed boar and grow crops in an organized fashion is useful. Having a small building for tools and storage surrounded by large fields and animal pens will be super useful.
Smithing house: This should be a larger building where you can place multiple furnaces and different kinds of workbenches. You could also keep your gold and other riches from your adventures here.
Portal house/ area: Keeping all portals close together saves time so putting them in a nicely decorated area might be a fun add-on to your base. Also, make sure to label them with signs for more ease.