I have been playing Warframe for a few years, and it is one of the best free-to-play games of all time. Normally in progression style free-to-play games, the developers put in artificial barriers to force you to spend money, but that does not happen in Warframe. What makes this better is that premium currency can be traded. That is unheard of in other free-to-play games.
If you are looking for a free-to-play live service game to play, then I recommend Warframe. Just proceed with the expectation that the game does not do a good job of explaining its systems or progression, so you will need to follow a youtuber who is dedicated to that game to help you out. In addition to that, the game is grindy but does not have some insanely low drop rate, so there is a light at the end of the tunnel. I think the lowest item drop rate is around 5.88%, not the 0.00000002% you see in other free-to-play games. There are also hordes of enemies, so it is not too difficult to get what you need. It is also rare to farm for something with such a low drop rate. These days I find myself farming the stuff with a 15-20% drop rate.
