Need Some Invertabrate Advice!!

[Pisces28]

I have a BioCube 29G and just added some invertebrates.
Wanting to get more, but not sure just how much is too much..

Currently Have:

• 3x Bumble Bee snails (tiny)
• 1x Turbo Snail
• 1x Hermit Crab (Not sure which but hes small and looks plain)
• 1x Astrea Snail
• 4x Nassarius Snails
• 1x Skunk Cleaner Shrimp
• 1x Fire Shrimp

I want some cool-looking inverts that have nice colors/designs.
Any ideas?