The ability to save a direct selection
Sometimes geometric transformations require a complex selection of certain vertices on one or more objects. Losing the selection because of a misclick is so common and frustrating... One should be able to save current selection to recall it if lost. This little buffer can be really very temporary, i.e. stop working if object topology has changed in the meantime. It would already prevent frustration on many occasions.
Illustrator allows to save, load and managed partial and full selection with Select > Save / Edit Selection commands.
UI is archaic, but it does the thing you want.
Please leave any comments regarding this feature here.
As for having a selection operation as an undoable operation — there is a separate feature request for this you can vote for: https://illustrator.uservoice.com/forums/333657/suggestions/34934953
Yes, totally agree. Or make the act of selecting an undoable action.