I made a quick model to keep 25mm sanding pads and rotary tool attachments organised.
 

I recommend stacking pads so the soft sides are facing out, this makes it easier to insert and remove the pads. The holes in the top perfectly fit 3mm rotary tool bits.
 

Mine is printed in PLA with no supports but I added a brim for my print (not necessary).
 

Let me know if you want any adjustments and I can add extra models.