I'm doing sprites of bottles of 32x32, but after check, I found this will be the 100th bottle colection of OGA. So, in name of make it worth the effort, I'm going to put an inmense amount of things in them.
Expanding the collection wasn't hard, every body went for blue red and green, so I added cyan, purple, yellow, black and white. Also I'm planing:
Dust in the mentioned colors.
Fungus in colors
Aquatic life: Fish, octopus, crab and frog.
Magic things: Fairy, a little demon and a blinking eye.
Insects: Scarab, firefly, dragonfly, scarab, spider, butterfly.
I'm going to do the small objects as 16x16 sprites. But I want more.
What I'm asking you is tell me every thing you can imagine, that can be placed in a bottle.
Aquatic life and magic things might be nice. You may consider plants for a terranum. You may also extend bottles to jars as well. Also try separating a potion bottle to four layers as bottle back/front, potion/liquid back/front, so that object can be placed in between these layers and programmers will also be able to modify their contents in the game.