Ok, so I have some ideas for effects. Here they are:

Motion blur
Shade (For like, dark (not evil) scenes)
Noise
Neon
Splatter

And an idea for rotation:

Left-right-free
It combines the “Left-Right” rotation option and the option where you can turn it in any direction.

Sounds good, right?

*EDIT*
More effect ideas:

Glow (adds a colored border around sprite, box should pop up asking what color you want the glow to be)
Cubism

For paint editor:

Lower resolution / raise resolution (Makes a sprite more retro - game - style (Raising makes it more HD)

Block ideas:

Motion:

Change rotation speed by (Insert number here) - Changes how fast an object rotates

Looks:

Put (Vector or Bitmap) mask over (Sprite) - Allows the Vector mask for Bitmap images / Low-res Vector For Vector sprites.