See Description.

Any Idea of how to get it?

try playing the campaign (or maybe just the what-ifs) in online VS mode. I was missing a few but after that i got em all. hope this helps.

I got all of them by going to free play set it up in private to min team 0 max 1 and required players 1 then you can either pick a defense game and leave it or play and get some free exp. also turn off everything at bottom of setting like overtime