I'm kinda putting my "eggs" in the basket of the other raids being drawn from FF1, 4, 11, 12 or 13 since they are the numbered games in the series, other than 5, that had Omega appear. Though some of them in "spin off" or "sequel" moments, such as 13-2 DLC pack or FF4: after years.

That said, Omega also appears in a lot of spin-off titles so it is entirely possible to draw from them.