Here's a thought...
Welcome to the site! If I understand you correctly you want to find a way to cut features into the shelves to display your shaving razors and accessories but the shelves are pretty close together? if that is the case, why not consider making some small pieces from a similar wood or complimenting wood that can be attached to the shelves with glue or double sided tape? This way they can be customized to fit the various items (brushes, razors, cups...) better and you can arrange them on the shelf for better viewing, instead of everything in a straight line.
Sounds like you have quite a collection! Next thing you'll tell us is you have a beard!
Just a thought.
Saw Dust Rules
“In God we trust. All others bring data.” - W.E. Deming
Dave in Rochester, NY