Can I access my old Polyvore account?
If you go to http://web.archive.org and type your old Polyvore url there's a good possibility some old snapshots were saved and you can see some of your old profile.
How do I find old sets on Polyvore?
You can type the old Polyvore profile address and homepage in the web archive and there should be Loads and loads of pages saved for you to find collections, sets and items and hopefully find items that you like. Maybe even old members you used to follow. Pintereest may also be an option.