#4 EC3
EC3 was a major star back in TNA/Impact and has had phenomenal matches in the promotion. Although, when he came to WWE, his overall momentum slowed down quite a bit. He was still a star in the developmental brand but after he was promoted to the main roster, he was turned into a mute piece of chiselled meat, majorly seen flexing at the mirror.
EC3 and Kurt Angle have a storied history from their TNA days. Even if they don't tap on that, EC3 is a much better performer to ignore and giving him the rub from Kurt Angle, gets him back on track.
#3 Bray Wyatt
Bray Wyatt was one-half of the RAW tag team champions in his last storyline in which he featured on WWE TV. After they lost the title, Matt Hardy announced his retirement which left Wyatt without anything to do. He has since vanished from the WWE TV except for some network specials.
Bringing him back to retire Kurt Angle could be the best way for his return as he would be back in a major program from the get-go and won't get lost in the mid-card.