You can use blueprints in Sims 4 to add a lot to your game. Any type of building could be considered a lot, such as a house or restaurant.
I keep my blueprint files separate in .zip files as a backup. This way I can share them here too and Sims 4 players can download and install them without having to use the Sims 4 gallery. This is also a safeguard incase the online Sims 4 gallery service stops in the future.