Here are some new horizontal work-holding clamps for my ShapeOKO 2 that I designed in Fusion 360 and printed on a Makerbot Replicator 2.
A video describing them is here: https://youtu.be/Z9x7S5f6Poc
UPDATE: I went ahead and made another version with slot spacing of 50mm, 75mm, and 100mm. The 75mm should work well on the x-carve. Let me know if folks need any others.
UPDATE2: I added two "long slot" files to extend the slots the full length of the clamp.
Printed at standard resultion on a Makerbot Replicator 2.