If you happen to have an umbrella stand that does not exactly fit your umbrella this might do the trick.

This is a parametric adapter that lets you define the diameter of both umbrella and stand - as well as the size and position of an optional hole for a knob.

It did the trick for our two sands - and should also work for others.

I've used ASA for the final one given its an outdoor application. For indoors PETG works as well.

The second element is a stabilization element that gets pushed into the tube of the stand - it gives the umbrella a better stand in the end.