I personally prefer neutral baby bedding and decor. I'm one of those people who really don't want my children to be pegged to colors or themes – blue are for boys, pink are for girls kind of pegging -- and neutral themed bedding keep me away from all that labeling.
Plus and this is a BIG plus, there's always the possibility that you can use them again for the next one. And oh! How about if you've decided not to know the gender of your baby? Then neutral baby beddings are the best way to go.
There are a lot of baby bedding collection that are considered unisex and it won't be a problem looking for these themes and colors at all.
One of the reasons for the existence of neutral crib beddings sets is basically to have an alternative to the usual blue and pink colors. Many baby bedding collection with neutral themes will naturally not be this color-biased.
Some of the available neutral-themed bedding come in the usual white, beige or cream. But you can also go a bit more experimental with black and white combinations, orange, yellow, purple, mint green or just plain black.
This is a bit tricky. For example, sports crib bedding sets are usually associated with boys. But they don't have to be. Many of them will usually be in blue but if you really want to buy one, you might be able to get it in a different color (and that should make it neutral, right?)
Anyway, to start your search for a unisex crib bedding, you can have one of the following themes: