Glowing Plants:

Useful for magical plants, save points, etc.
Cracks:

Useful for breakable floors and ice puzzles.
Bubble/Orb:

Made with the Water3 animation.
Useful if you need a bubble or an orb for whatever reason.
Crystal Ball:

Useful if you need the crystal ball on a different kind of table or that you can interact with.
Tiny House:

This could be useful if you have a race of tiny people or if you want mice to be homeowners!
It could also be useful for use on your World Map/Overworld.
Tall Cactus:

Useful for adding variety to your deserts.
Also has cacti with flowers.
Note Men:

Note Man and Note Twins.
Useful if you want music-based enemies or creatures
Meteors:

Useful if you need a meteor/comet in a cutscene.
NOTE:
1: Directly from Meteor.png
2: Centered
3: Directional meteor
These are 192x192 (The same as each individual frame for animations).
If you need a bigger or smaller sprite, feel free to resize the meteor images to whatever you need.