Suggestions for my new addition?

I don't plan to add anything for a little while but I am literally stumped on what I want to add to my happy little family.

I am looking for suggestions,

I currently have;
10 blue leg hermit
2 emerald crab
3 chromis
2 true clowns
1 coral beauty
1 Valentini puffer

Everyone lives amongst each other masterfully and I don't want to disturb that. Any ideas?

Thanks!