If you ever see a Bill the Cat plush from the Bloom County comics, be sure to pick him up because he sells well on eBay.
It's the most common lesson from my videos: look for things that STAND OUT because you haven't seen them before. Then, use Google Lens to IDENTIFY the item and then use keywords to look the item up on eBay.
It's really just that simple. Even if you had no idea what this item was or if it was valuable, 30 seconds with a smartphone would show you exactly what it was and what it sells for online.