I'm going through an experimentation phase now, after having a pretty consistent and small closet and color range for awhile.
My main neutral is black, but gray (in a range of tones like mrs eccentric describes) is recently taking over.
The teal turquoise mint green range is my newer main accent.
There are a few shoes/jackets in earth tones: olive green, mushroom, and dark grayish brown. They generally work well with almost everything else.
I used to wear a lot of deep red, but have almost none of that now, but do have some deep coral/pinks. This is a big departure, but I'm really drawn to it and it seems to work with my coloring, have to see how much gets worn.
Trying navy/ink blue but having trouble getting the exact shades to match is making it a sideline rather than main neutral.
When I'm shopping now, I mainly shop for one attribute at a time, since I'm scanning thrift store and off-price retailer racks. So I'm either searching for color (I recently added some bright white and lilac), or another single attribute (pointy-toed flat, longer narrow neutral skirt).