Neutral, neutral, neutral all the way, I'm afraid.
Boring, I know, but your buyers want a clean canvas so that they can visualise the space and how they will live in it.
Added to which, neutral wall colours maximise the light, look great in photos, make your artworks look fantastic and compliment furnishings if you have them.
There are no set rules. If you have a beautiful Hamptons home with some bedrooms in muted blues or pinks, that's fine. But in an apartment, a variation of white is best.
I like to use Dulux paints and recommend Vivid White, Whisper White, Stowe White or Antique White USA for properties with neutral-coloured flooring - timber or carpet. For more depth and warmth I like a Half Hog Bristle. For more contemporary homes, I also like Natural White, Lexicon or Quarter Lexicon. Personally, I like the contrast of White on White or skirtings and doors - why over-complicate things?