Grim Dawn, one of the best action RPGs ever made, is just $5 right now on Steam. You should definitely check it out.
If you're a Diablo fan who grew up with the original Blizzard classic, or even Diablo II and it's epic Lord of Destruction expansion, then you might want to pick up Grim Dawn. This aRPG is a lot like those older games with a darker tone, more streamlined mechanics, and a few innovations thrown in for good measure. Grim Dawn is a pure loot-driven aRPG and even features online multiplayer so you can team up with your friends.
Diablo 4 is a long ways away, and the market simply doesn't have many aRPGs. You might've picked up Torchlight II for free on the Epic Store and that'll hold you over for a while. But if you're looking for something that's more violent, more mature, more grim, then definitely drop a fiver on Grim Dawn on Steam.