All of your unsold listings over 90 days old are gone within eBay's Seller Hub. There's a "very slim chance" that you could access a few of them outside of the eBay platform (sometimes eBay will drag their feet for a little while on deleting everything older than 90 days). To "possibly" access an unsold listing older than 90 days try this: go to your personal email account and click the old link of the eBay Relisting notification (you have to have the Items Unsold Notification option set up in your Seller Account which I think is the default parameter).
If this doesn't work search for the item on a web browser. Sometimes the old item will show up in the search results of another website. Click that link and the old listing might be there with a Relist option within the webpage. I'm speaking through personal experience of the same thing happening to me several years ago. More than likely you'll get the eBay "We Looked Everywhere" error message on these old listings but a few may still be accessible.
Now, I store my item photographs in computer file folders and write my Item Description in a word processor and save the text file. I include the item weight and box dimension notes next to the text of the Item Description. That way, I can easily copy and paste the Item Description from my text document into a new eBay listing page if the original listing page is unavailable. Good luck!
