#2 Tommy Dreamer
Tommy Dreamer is a hardcore legend, having been an important part of ECW and then WWE. Dreamer joined WWE at the end of the Attitude Era in 2001, after ECW shut up shop.
He won the Hardcore Championship on 14 occasions, as well as the ECW Championship once when it was reintroduced in the WWE. Dreamer spent nearly a decade in WWE before leaving in 2010 and then joining TNA following which he had another brief run in WWE in 2015.
At AEW's Double or Nothing show, Dreamer participated in the battle royal which was eventually won by Adam Page.
It was later revealed that Dreamer was backstage during the show, working as a producer. According to PWInsider, Dreamer was working as a producer even at last month's All Out PPV. We could very well see him feature on AEW television as well as work backstage for the new promotion.