A tool I just discovered back when they had a Kickstarter Campaign nearly a year ago is the Dimide Clamp. I supported them on Kickstarter back then, but after it failed to meet the goal I was hoping they’d still find a way to launch which they just did.
They look similar to the Kant Twist clamps, but the screw is in tension instead of compression which should allow greater load since it won’t buckle. They’ve also shown themselves taking the clamp to 8,000 lbs of clamp load recently and it didn’t seem to plastically deform at all. Would be nice to have something I could use when I need to keep a part still. Am currently waiting to see if any reviews come around prior to purchasing though.