I have gotten the following "free" upgrades on AA:

Operational Upgrade
LAX-LAS (PLT)
JFK-LHR (GLD)

Flight cancelled and only room for rebooking was F:
LAS-DFW (PLT)

Bumped and rebooked into F on a later flight:
MCO-LGA

Admiral's Club AAngel was nice to me even tho Y was not full:
DCA-MIA