People have been asking for a backup/restore guide for some time but I think since it varies a bit from game to game, no one ever took it on.
There are several mini-summaries here: Restore backup on new server - #15 by Daniel_Ertl
Otherwise, I would search the forums for any games you have installed. Also, I wouldn’t wipe the old system until you verify the new copies are complete/working on the new system.