I have my torrents saved to three drives and need to replace one of them.
How can I select torrents by drive/path so they can be moved?

i don't think there is a way to search for torrents by path.

the easiest place to find the path is on the options tab of the transfers tab.

if you had had the files in categories by drive letter, or had set a description for drive letters, that would make it easy.

if all or most of the files on that particular drive, and not the other 2 drives, have something in common, like same tracker, something

in the file name, etc... you could search for it.

I had a similar problem.  Managing 1000 or so torrents in different locations across 7 drives.  I could either use the category system (which would have left me with a silly number of categories) or rename my torrents.

If the categories could be managed hierarchically (as in qBitorrent) I might have chosen that route, because I didn't want to break the high level categorisation system I already had in place.  However, because they weren't I elected to go through all 1000 torrents and rename every single one, prefixing each one with my own naming system.  It was worth the effort.  Now I can find every file in a given location by using it's prefix and move them around en masse using Tixati's own relocation function.  And it's easy to keep on top of.

Besides Categories you can also use Descriptions. It is an optional column with simple text field for each transfer on list, enabled in Layout > Select Columns... > Description. You can select many transfers and give them the same description. You can later sort transfers by Description column or use Text Filter on Descriptions. In order for this to work first enable Description in the Text Filter menu, use the button on the right side of the broom button.

Details with pictures are on the Help page: https://support.tixati.com/descriptions