Hey there. Just was looking around in Brickset's parts database
for a few minutes earlier, and the minutes turned into hours, and long story short I have found enough unreleased parts to identify at least 16 unreleased minifigures that could very easily be a future minifigure series:
Honeybee Suit Guy
Painter (like a house painter, not an artist)
Native American (probably meant to look Aztec? Lots of gold; lots of body paint)
Valkyrie? (some type of historical/mythological female fig)
And finally, here's a Eurobricks post
where I have links to all the individual pages.
On a side note, while I was making this post, my twin brother pointed out that another Eurobricks member found another fig: a baseball catcher in an "away" uniform. That kind of kills any chances of these being one complete series, but they still could be multiple series. My EB post is edited to include this fig.