The best Mafia game in it's franchise is free for a short period of time (sep 2-5th) in steam. The story line of Mafia 1 is solid, even if it's graphics looks bad. Everyone must play this game.
Available inside Steam: Download
This game has good graphics and also good story line. If you like adventure games, this will be the best in that category (after uncharted). Free for Limited time 7days.
Available inside Epic Games: Download
I haven't played this game, so I can't give a honest opinion about this game. In the description it's mentioned that it's a non-combat exploration game. I'm not a fan of non-combat games.
Available inside Epic Games: Download