Not sure of any place other than eBay (and places like eBay) to suggest. But if you don’t mind a resource site (showing different ponies etc.) there is this website.
I don’t know the terminology (I just collect ’em, I don’t read up on them), but I have a boxful of old (’80s) ponies in my closet. Trouble is, they are all refugees from thrift stores and yard sales and don’t have combs, brushes, ribbons, etc. with them. Any interest at all?
It's not hoarding if it's books!
Cat hair -- condiment and fashion accessory!
Check out the My Little Pony Trading Post! They’ve been around a long time and I’ve bought ponies from sellers there before — lots of knowledgeable, loving collectors there!
Interested in buying or trading for: GB Pebble Sitting Red Fox in dark grey, Lap Dragon Test Paints (Water Sprite, Glacial Pearl, Opulence, Pastel Rainbow, and many others - see my Classifieds ad), Blue Morpho OW, GB Pebble Loaf dragons in blue/aqua/teal, and Griffin Test Paints (Black Rainbow or Frosted Jade).