Streets of Rage 4 is one of the best beat 'em ups I've played in years. Highly recommended. My favorite characters are Estel and Blaze.
Luigi's Mansion 3 is also fantastic. Lots of personality. I think Luigi's Mansion would make a better movie than just Mario.
Bowser's Inside Story is probably the best of the Mario & Luigi games, and one of the best Mario RPGs overall. But Brothership is coming out next month, so we'll have to see how that fares.