now see, this is a VERY hard question, so instead i have a top three.

Number 3: SFA2, i really love the custom combo system, and that just makes this game better to me than any other SF game
Number 2: MK11, i love the mk series, and i like the new fatal blows, and the way the characters play
Number 1: SSBU, this is literally the hall of fame for gaming, it has so many unique characters with unique moves (aside from FE), and plus, it has a form of character creator!