@way77 said:

Discovered the trick... duplicate the list, delete first one and then the copy. Both color lists are gone.... finally.

What worked for me: duplicate the EZdraw list, but remove the " copy" suffix that is automatically added to its name before clicking "OK." Then delete it & SketchUp will pop up a dialog box complaining that it can't delete "null" but both copies will be gone when you dismiss the dialog.

EDIT: This method does not persist -- IOW, the EasyDraw color palettes lists will be gone, but they will reappear the next time you launch SketchUp. To get rid of them forever, check the ~/Library/Application Support/Google SketchUp 8/SketchUp/Materials folder (the user Library folder, not the system or root level ones) for any folders with a corresponding name (like "EasyDraw") & trash that folder.

Also check the ~/Library/Colors folder (again, the user Library folder) for any files with the extension ".clr" with names corresponding to the unwanted EasyDraw palettes (like "EZD_WebSafe.clr" or "Toolbar.ezdraw.clr") & trash those too.

Note that Easy Draw creates these color list (.clr) files the first time the app needs to access something that uses them (like the Easy Draw toolbar) so if you run Easy Draw after removing the unwanted color list files it has already created, it is still possible that other ones will be created & show up in the SketchUp Materials lists (or that you will get unexpected results if it needs one you have removed).

FWIW, page 14 of this Easy Draw version 3 manual lists all the color list files that version might install, & may be helpful in determining where some of the "mystery" color palettes came from.