Cosmigo
ProMotion has been recently updated. Now it has proper layers (photoshop style), pixel-perfect drawing and with already present awesome tile mapping engine and palette editor, it's the best pixelart app you can have. If you run on Windows that is.

If you don't, there's the close runner-up
Aseprite which is multiplatform and has great animation features. Not so great (read: not existing) support for palette editing, dithering or tiles. But it is in quite active development.
I think that's the only two pixelart oriented drawing apps that have been updated recently. Others like
Graphics Gale and
Grafx2 are in a development limbo of sorts...