Lake house
Some kind of Boat house
Maybe a Boat for people who love to live in the water
Dock
Lighthouse
Basketball Court
Sugar Cane Farm

I like these ideas.

For the dock, we have something similar already. Have you taken a look at the Fish Pond?

I would say the dock would be used like a bridge with only one end on land, for putting into a lake / ocean.

@brisingraerowing The Instant bridge can be used like this already, it's smallest size is currently 25 blocks which may be too large for a dock, maybe bring that down to like 8?

That would probably work.

Closing this issue. If there are more suggestions please talk about them with the rest of the community on our discord server!