Shovel Knight in Super Smash Bros. would be awesome. He will be an assist trophy for Smash Ultimate, but if you to see the knight battling in a platform fighter, then check out Rivals Of Aether.
Rivals Of Aether is an indie platform fighter (Smash-like) and adheres closely to the Smash style of play- build up damage and smack your rivals off screen. Rivals Of Aether is built with the competitive community in mind, featuring in-depth tutorials and tools and online multiplayer. It also has an extensive single-player story mode too, not to mention a good chiptune-based soundtrack.
With the addition of Shovel Knight, he brings in some interesting moves to the game. His trademark Shovel Drop (the pogo jump) is part of his combos and his moveset reference a lot of the indie darling game he appeared on. Rivals drop gems when Shovel Knight hits them. Taunting will summon Chester to spend these gems for upgrades, which opens up different playstyle options. He can even stop and fish for gems.
In short, he looks rad:
Shovel Knight is a paid DLC, which also includes his own new stage, coming in September. While the base game is now only RM31 on Steam, a Definitive Edition of Rivals Of Aether is coming soon which includes all DLCs, more online features and more next year.