I know there are already a few available but I did not find exactly the one I was looking for :-)
Anyway, with some inspiration from the existing designs here is my small filament spool.
It is quite sturdy but the weight is reasonable (about 35g of plastic).
The diamater of the filament roll is about 20cm and it will hold about 400g of 1.75mm PLA filament.
A 608Z bearing can fit in the center of the hub.
Print the single plate which includes all the required parts (1 top hub, 1 bottom hub and 3 forks).
Assemble the spool using 3 M3 screws and nuts.
- Roll up some filament and upload a picture :-)