Paraster
Smash Lord
I've felt for a while that Smash Bros. adding an indie fighter is both inevitable and necessary. Between how many potentially great fighters there are and how large and significant indies have become, it would frankly be shocking if they don't end up adding even a single indie fighter.
My top choice for both desire and likelihood is Quote from Cave Story. His game is often considered the quintessential indie game (or, at least, it filled this role earlier in the history of indies), it has appeared on Nintendo consoles multiple times, and his multiple different guns could make for interesting attacks.
Other choices I'd like to give an honorable mention to include Reimu (Touhou), Shantae, Shovel Knight, Cadence (Crypt of the NecroDancer), the Knight (Hollow Knight), Kris (Deltarune), Frisk (Undertale), and Hat Kid (A Hat In Time).
My top choice for both desire and likelihood is Quote from Cave Story. His game is often considered the quintessential indie game (or, at least, it filled this role earlier in the history of indies), it has appeared on Nintendo consoles multiple times, and his multiple different guns could make for interesting attacks.
Other choices I'd like to give an honorable mention to include Reimu (Touhou), Shantae, Shovel Knight, Cadence (Crypt of the NecroDancer), the Knight (Hollow Knight), Kris (Deltarune), Frisk (Undertale), and Hat Kid (A Hat In Time).