Coming from the Super Smash Bros. Director's Room:
"Pic of the day. Here's Beat! And Plant Barrier!! These are some of Mega Man's custom special moves. You might also be able to use some signature boss-like moves from the Mega Man series, too."
As explained in an earlier update, "each fighter possesses four special attacks; standard special, side special, up special, and down special. Each of these can be customized, however, so there are three variations for each direction. This means there are two classifications for special attacks: basic and custom."
Question is, what other "signature boss-like moves" (or support characters) can we expect? Board the speculation train and sound off in the comments below!
Source: Director's Room