I would have loved to have seen a cameo or larger appearance of Kevin Reilly, back in the day of original series movies.
He almost made it. A ST VI publicist hosted an audience poll at a big US convention. They voted out Riley by a very narrow margin, and that's how Janice Rand returned as Sulu's communications officer. Then her lines were cut when Christian Slater was suddenly given one of her scenes: waking up Sulu.
some of the DS9 characters in a movie like Gul dukat, Garak , Quark, or any of the station crew.
Quark's cut scene in "Insurrection":
Quark on the Ba'ku planet
by Therin of Andor
, on Flickr