I have recently fallen into the habit of reading Buffy fanfiction and a surprising amount of it makes reference to Xander being slightly more than human (by more than simple experience). This surprised me since his role on the show was primarily 'the normal guy' and 'the heart of the team'.
I began a bit of a re-watch of the early seasons and I have noticed some times when he was affected by magic/demons/various supernatural stuff that could have given him enhancements beyond strict human norms, such as his possession by the hyena spirit, aerosol steroids from the swim team, and his well-known acquisition of military know-how from a Halloween costume.
What other events has Xander been part of that could have enhanced him beyond the norm?