I found one that tracks stats for RB and WR, but I'm specifically wanting one for kickers/punters. I would love something in the vein of "Mobile Soccer Coach", which is a good app for tracking in-game soccer stats.
If I were creating the app:
Kickoffs (Yardage, Touchbacks, also way to mark if it was a squib or onside)
XP (Attempts, made, aborted)
FG (Attempts, made, aborted, yardage, which hash mark or centered)
Yardage (Line of scrimmage/return yds so that net avg can be computed)
Hang time (wouldn't be necessary to have its own stopwatch with so many in the market but at least a place to record it if user chooses to time it with a stopwatch app)
Ability to enter in a schedule and track stats throughout season and ability to share stats in a legible report
Editable player name(s) and team(s)
This is an app I would love to see and definitely would be willing to pay for it.