This topic is specifically made to promote Multiplayer games made by participates that I think deserves some attention for effort. If you think you deserve to be on this list, message me on reddit or discord or in this community post.
Car Crash Armageddon is a cool little game made in 3D by alessandrovinaccia. It has relatively nice graphics for something that runs super smoothly on my weak laptop. The controls are tight in game and the physics is stable. However, the community is nowhere to be seen since the marketing was rather weak. If you do want to play, get a friend to download it as well and play together.
Car Crash Armageddon, check it out.