Alright, just thinking of some subjects that might make for useful videos.
Grass, dirt, bricks, ie the stuff everybody should know. Basic videos for the way to create tiles in any app, advanced videos using Pro Motion's tiling capabilities.
Large character sprites
Fighter, RPG battle screen, side scroller, etc. Larger sprites would probably need to be divided into multiple movies, lines, colors, shade, AA.
Fonts and interfaces
Title screens, HUDs, dialog boxes.
Pro Motion specific. Never tried it before, but I'm looking forward to seeing how it's done/thinking of trying it out myself.
A big project to tackle, would probably be a long video. Setting up basic motion, key frames, tweens.
Some work of art, fairly large and detailed. Best bet would be a timelapse, 4X or maybe even 8X speed.