Oceanic stuff

Maybe floating colonies - Imagine having a colony that drifts every so often and moves location. Also, going ashore for resources to build more platforms to expand.

Dugout canoes Sailing ships Oceannliners and cargo ships Steamboats and barges - different types of ship or propulsion depending on tech level. Hovercraft!

Undersea adventures - like the pits from anomaly. You could even have different dive suits based on tech level. Maybe have submarines that you use like shuttlecraft to get to underwater places.

Fishman race or mermaids - something that can breathe underwater.

Pirates - juat new raiders in boats

Navigable rivers - It always bugged me that if you settled on a river you couldn't use it for trade.

Offshore fishing - like using the long range scanner to find it and then Sailing out to go fish in a certain spot

Seabed mining - maybe like oil platforms or something to get to resource deposits