I reckon it is more fun to roll your own better quality workarounds
As part of upping my woodworking tool collection I added a Bobbin sander to the toys, partly for finishing off Templates, Enclosures and Laser Cut edges as well as general use.
Triton thought of on board holders for ALMOST everything but forgot about the spindle tension washers which will almost certainly get lost over time
There are six different dust plates and one will almost always be fitted in the sander so it leaves a slot free to make a 100mm diameter disc to hold the washers. So out with Fusion 360 and roll up a model to 3D print. This could have also been Laser Cut as shown in acrylic or 3mm Ply with the front face where the large washer sits would need a heavy engrave or sanding as it is a touch over 3mm thick.
With the model I made for 3D printing it took me under 10 minutes to create the Laser version using the same basic sketch as shown so 3D print or Laser use the process that suits best. Currently making the 3D printed one and I might make an Acrylic one next time I have some on the Laser.
Someone better find me some TEA worth buying woodworking gear is sending me broke
Edit Added a picture of the printed item.
Edit of the Edit Added a couple of pics of a Laser cut MDF one while I was cutting some other bits.