There are only 8 mystery episodes left, 7 if you count knowing names (which Episode 19 has a name already, just no description or air date yet).
Only so much room left for possible Scootaloo and Celestia episodes. :c
This season is likely to wrap up by the end of April, or the beginning of May. It feels like it has come and gone rather fast, Season Three is unlikely to air until late Summer/Fall like Season Two did.