Best Free to play game on Mac

I have been using Mac for several years, but I never found a good free to play game on the app store. I have to go on Steam to download them and play.
Finally, this game came to save the day. I can’t put my mouse down once I finished the first battle. It’s just so fun!
But here comes the problem, the game isn’t very scientific like another tank game that I played called “War Thunder” (not on the app store). The game uses a health system, and surprisingly, HE shell does the most damage. This doesn’t make sense to me since HE shell just damage the outside of the tank, but not the crew members. Also, I didn’t receive my gold after I spend five bucks purchasing it.
Overall, it’s one of the best free to play game I played on the mac.

Sam_525 about World of Tanks Blitz PVP