Amibay is the one that springs to mind off the top of my head.

I use it widely, but is more focused on Amiga

vcfed.org/forum

yeah that's what sucks the one site that EVERYONE uses is vogons, you can list on other site but, you don't get the views that vogons gets. i give away old PCs and macs and hardware but, it's hard to find it all home or get in touch with everyone from all the different forums. they do NOT allow sale or trade here but, they ALSO do not take kindly to folks trying to give away stuff here either.

It’s easy to understand why it’s not allowed though I think - even the eBay links thread ended in tears. Mods have better things to do than control that can of worms.