I'd love to see even more options for what can be put into a flower pot!

Here's some ideas:
Nether Wart
Chorus Fruit

Kelp and Lily Pads (dirt texture in pot replaced with water texture?)

Corals (Wet looking pot soil texture, would only accept the regular corals, ie not fans or blocks)
(Possibly support Upgrade Aquatic Corals?)

Sea Pickles
Seagrass
Vines/Cave Roots - Could hang from the sides of the pot, like Cocoa Beans do

Apples (Maybe? Could be attached to a tiny bush)

And possibly mini-versions of the two-tall flowers

Please use the quark subreddit /r/quarkmod for suggestions.