Bathoom Storage Shelf Ladder Shelf Wood by KnottyByNatureDecor
Just towels- could use pvc pipe, spray painted. This copper pipe towel rack would work well in a small space. The copper does not react with water.
Toiletry holder - WC set Toilet brush holder Upcycling Klo - a design piece by KonzeptFrei on DaWanda
Over/next to toilet? DIY Wall Shelves - How to Make Hanging Storage for an Organized Bathroom (tutorial)