Team Fortress 2

Team Fortress 2 is perhaps one of the best free shooters. The game for its age (11 years old at the time of writing this comment) is an excellent example of a game with many mechanics, modes and strategies. TF2 does have donations, but these are just accessories and taunts that add its charm to the game. TF2 is still in the top 10 on steam, and do you know why? Because it is very flexible and understandable for beginners, and, unlike many other shooters, it has a non-toxic community.