#2 Evolve
In 2015, WWE formed its current partnership with Evolve. Presently, WWE is allowed to scout Evolve talent to sign for WWE NXT. This partnership has further progressed to WWE talent appearing regularly on Evolve shows, with notable names such as Velveteen Dream, Triple H, and William Regal appearing on various shows (watch the video below).
Primarily, WWE and Evolve's working relationship has been generally successful. It has generated buzz on social media, specifically the involvement of the Street Profits. Moreover, it has provided a platform for Evolve performers such as DJZ and Austin Theory to work with WWE talent.
Considering that Triple H himself debuted in Evolve at their event Evolve 54, it proves that WWE wants to work with the promotion. Moreover, when Triple H surpasses Vince McMahon as head writer, things will only improve further. Therefore, now is the right time to conduct more WWE/Evolve crossover events. The possibilities are endless.