Let's take a look at what game modes are available to play online! Some of them are programmed into a game, and there are also a few that are custom modes, that were created by hosts and players.
Racing (pick-ups on): Arguably the most classical way to play. Weapons are enabled, therefore RNG also plays a huge role, but you still need a lot of skill to utilize these weapons properly. This mode is usually raced with 3-4 laps on each track, and it's the one that most sessions use.
Racing (pick-ups off): The other main way to play races, however, going quickly is much more important in this one than with picks on. There are no weapons... just you, your car and the raceline. On these sessions, the most common lap count is 4.
Teams [Custom]: Teams is a form of racing with a special set of rules. Before the session starts, the participants are seperated into 2 groups, (usually 3-5 members each), and of course, they fight. Pick-ups are enabled for these events. However, what allows for more room of strategy is the fact that people, who are too far away from the leaders, can go the other way, and kill the other team's members. Lap count is usually 3, and usually at least one member of the team goes back on lap 1. The points are scored as the following:
Battle Tag: Usually played with pick-ups on, it is an original game mode. Not as popular as the racing modes, but it has its own tactics, and it's also quite interesting to play. At the beginning, people look for a star pick-up. However, in Battle Tag, it won't give you a weapon. You will get a green zap around your car, and you need to keep it for as long as possible. When you get close to another car, the star gets passed, so you need to stay away from other players if you have it. As soon as your time passes (visible in the top right of the screen), you finish the battle. Whoever gets to 0 seconds left first, wins!
Time Knockout [Custom]: You have to beat a better time in each race, otherwise you get eliminated. On each track, a final race between the survivors follows.
Car Variety [Custom]: You can only use each car once! Therefore, you have to use a different car on each track. Usually played with 5 allowed tracks & 5 allowed cars.
Best Lap Session [Custom]: Only people's best laps count, as the name suggests. Lap counts can be really variable. Sometimes a Time Limit is set for the races.