If you consider some of the other X-Men characters from the TV show and comic book series, there are considerably more options.
For example, "Maggott" has no abilities of his own...he simply had 2 super-powered maggots that lived inside of his belly.
"Warpath" has "superhuman strength, speed, stamina, agility, reflexes, durability, and senses"...but this could feasibly be achieved through working out, training, or taking stimulating drugs.
"Karma" has only one ability which is mental possession of other people -- an ability that some hypnotists already claim to have over suggestable people, to some degree.
However, I think the most mundane superpower of all goes to "Forge," who's ability was simply "superhuman inventive genius"...and we've already witnessed a few people like that on this Earth, like Da Vinci and Einstein.