For used items, eBay is the best place to go. Amazon makes it more difficult to sell old products, but Postmark is ideal for clothing. Mecari is a good combination of eBay and Poshmark, with a lot less traffic. My own opinion of Mecari is that it is more hobby friendly than business friendly (albeit that may have changed since I last used it)?
Facebook Marketplace is a platform that allows you to sell Online sales are becoming increasingly competitive in the industry and attracting shoppers' attention.
I haven't heard anything about OfferUp's internet sales.
I'm not sure what your problem is with eBay; it's a really good site.
If you're selling vintage handcrafted items, Etsy can be a good option.