Posted on the store's Discord Battletech Resources and Facebook Event Page for our weekly games:
Floating Criticals
Elevation Changes while Moving Backward
Enhanced Flamers (Give Damage and Heat)
Rapid-Fire Machine Guns
Sprinting
One Arm Prop while firing Prone.
Evading Movement
Guarding Movement
Careful Stand
To be fair, we haven't used Evading or Guarding Movement much. Honestly, I'm not one to sacrifice fire for pure defense. Killing a target so it can't hurt you is the best defense.
In addition to that, we have a narrative campaign going at other times that adds Quirks to the list.