I was an Ebay reseller for many years and one of the hardest parts of that business is sourcing the goods to resell. I was spending hours scouring through Gumtree and Craigslist for undervalued items to buy and sell on for a profit, as well as Facebook marketplace, and looking up collection only items on Ebay. Although I could find the goods to sell and was making money, it was a huge amount of work, and although there were a few helper tools I found for Ebay buying, none were what I wanted.
Fast forward to a few years later, after a mid life career pivot into software I decided to develop FlipSource. FlipSource is an app that has a selection of smart searching tools for deep searching ebay and digging out the hidden listings that 90% of casual users will miss. The primary tool is the local search tool, which searches and returns listings that are only available for collection within your area by distance. These tend to be larger and bulkier items that are possible to ship (though lots dont bother), or job lots of goods where a seller just wants some space cleared.
I'm not going to go through every feature in detail but the other most useful tool is the Vague Listing finder, which uses a custom algorithm to retrieve listings that are light on detail and description, meaning they get missed by most peoples standard searches through the ebay site. You can find them by category searching for hours, but this just saves you the effort.
Best part is it is free to use, you don't need to log in or create an account, and no one is going to bombard you with unsolicited emails or push messages. So go check it out.