The CoCo Counters / BG Aggro deck only runs a single copy of Drana, Liberator of Malakir. But the Collected Company-fueled deck has a good reason to include her. The deck is based around Winding Constrictor, a creature that adds an additional counter whenever you, an artifact, or creature you control would get one. The deck is loaded with creatures that create +1/+1 counters such as Longtusk Cub, Rishka, Peema Renegade, Tireless Tracker, and Verdurous Gearhulk. Drana's ability can give your creatures two or more +1/+1 counters depending on how many copies of Winding Constrictor you have on your board.
The Hardened Scales deck is also based around the Winding Constrictor, but also around an enchantment called Hardened Scales. It does the same thing as the Constrictor, but only for creatures. However, being a one-drop Enchantment, it can come down on turn one and proliferate counters much more quickly. The deck hasn't had a super strong showing just yet, but Hardened Scales decks were very good in their time in Standard and have been popping up here and there in Modern, as well. We'll see how well they hold up in Frontier.
The BG Aggro deck is performing fairly well on Magic Online in unofficial tournaments. Whether this deck becomes a fairly good deck in the Frontier format or not remains to be seen. At the very least, players are now interested in Drana again outside of having a copy for casual Vampire decks and EDH.