Garrison Kane

Garrison Kane was a person, possibly a mutant, about whom some form of information was known by William Stryker.

X2: X-Men United
A folder titled with Kane's name appeared on Col. Stryker's desktop when it was accessed by Mystique.

Trivia
In the comics, Kane was a mutant who possessed the ability to transform weapons attached on his body armor and to access all recorded mutant powers and use them. This has not been explored in film to date.