Ever since the New52 these boards have been full of demands for returning characters who were oddly absent.
I feel like in the past few months, several of the most consistently requested have returned:
Stephanie Brown
Wally West (like it or not)
Donna Troy
Even some minor requested characters, such as Maxima have recently reappeared
So who's next? I think Cassandra Cain and Tempest are the other names I see appearing the most frequently.