Purchased a desk that fit the space available, but soon discovered the lack of a keyboard and mouse pad space.

 Removed the fabric drawer, the frame is approximately 21mm square bar, if you have one of these desks, this will work for you. ( bought from Am a Zon)

The rail/shelf brackets attach by friction on the bar, print 2 on their side no support needed. Print the mouse platform on its end with tree support . A pad for the mouse and pad strip for the rail I printed in black tpu, files included. Also a bracket to have the platform further out ( use for either mouse or keyboard platform)

mouse platform simply places on top of the 2 rails. Will be making a keyboard system also, waiting for a larger printer for that.

If you use the extended rail, scale down the length of the rail by 5%, or scale up the front to back of the platform by 5%. extended rails designed a smidge longer, so to fit in the shelled bottom of the platform.