Mankind
Description
One of the earliest examples of the genre known as "massively multiplayer online real-time strategy," Mankind was released in 1999. You are in charge of a large number of spacecraft. You begin with just one vessel, but you can eventually have as many as a few thousand at your disposal. To achieve your goal of becoming the ruler of the universe, you can also inhabit planets, form guilds, and wage war against other players.
However, after a certain period of time, a monthly subscription cost will be required in order to continue playing the game.