Stocking Suggestions - looking or that "last fish"

[digital-audiophile]

So I am looking for that one (or maybe two) last fish to add to my aquarium.

Currently I am lightly stocked but want to keep it that way. My tank now has a mix of softies, LPS and SPS since my upgrades to T5 and zeo.

My current stocklist as follows:

1 - Purple Tang
1 - Regal Tang
1 - Six-line Wrasse
1 - Sleeper Goby
2 - B&W Ocellaris Clownfish
1 - Skunk Cleaner Shrimp
1 - Blue Tuxedo Urchin
1 - Red Starfish


I'm just not sure what else to add?

- Butterflies and Angels are out as I don't want to risk nipping.
- I love Tangs but 2 in a 90 is more than enough already
- I have thought about schooling fish, chromis, anthias etc, but a 90 is kind of small for a decent school.
- Benggai Cardinals? Perhaps but not a very active nor colourful fish

Thanks for the advice and input.