So, I am keeping with my black grey and white theme. I dont know what should be added to my avatar, so any suggestions will be greatly appreciated. I mean should I perhaps change my theme too? Is this an overused theme?

I think you should Download the MAC and look at the items. It's not fully updated, but almost. Some of the prices may be off, but yeah.
I suggest getting an eyes of the wild, using the black cartoon eyes, and making an old cartoon avatar.

Thanks for the advice ^^ i will look at them and see if they will be nice.

Yeah.
The eyes of the wild are not in the MAC, but you should try making an old cartoon for sure.
1 tip with items:
It can be perfectly balanced, but the items have to be cohesive. Like boots, shorts, and a buttoned top shirt wouldn't be good.