Here's some ideas I've had and want to get out on paper before they disappear into the void:

Human goes to equstria ( I know TOTALLY original). But lives in the Everfree with Zecora's younger brother who sucks at rhyming.

The story of why there's no male alicorns. And one disguising himself as a tall Pegasus.

A day in the life of spike.

An interview with discord.

And something about somepony named Shade the Pegasus.