1.) Artemis Space Bridge simulator
Artemis is a game that is kind of like Star Trek in the sense that each player is a crew member on a ship. Each member has a job or two that they must do in order to keep the ship running properly.
Some of these jobs deal with the actual structure and navigation of the ship. Others can deal with combat or even communications within the sector.
Overall, I think this game is really fun to play. It can also get very hectic when you have multiple crews of people in the same room.
2.)Open TTD Open Transport Tycoon Deluxe
What if I told you you could go back in time and be the owner of a corporation of transportation. In this game, you play as a transportation company that is meant to transport goods and people across a generated world. You begin with nothing but a few loans to get yourself started. There is a variety of means of transportation. You can use plane, train, road vehicle, and even ship. The terrain in the game is also dynamic. You can create canals and locks, and, tunnels. You can even flatten terrain or build it up with landscaping tools. You can also plant trees or even tear down entire forests.
Both of these games have competitive multiplayer that is perfect for friends. Both of these games are also very sand-boxy games in the sense that you aren't really bound by specific rules.