The Raft is a Steam-based survival game where you start with almost nothing floating around the ocean on a small wooden raft, collecting ocean trash and using it to build tools and expand your raft.

Taken from the steam site:

Raft throws you and your friends into an epic oceanic adventure! Alone or together, players battle to survive a perilous voyage across a vast sea! Gather debris, scavenge reefs and build your own floating home, but be wary of the man-eating sharks!

The game has had multiple updates, including island-seeking radar and agriculture that can be harvested to make more goods.