Powys is the heartland of the Welsh pony and cob. If you want a Welsh section A, B, C or a Welsh cob, this is where the studs are — many of them long-established, breeding the same lines for decades. Buying here often means buying from someone who knows the pony's dam and grandam and can tell you exactly what temperament runs in the family.
It is a big, sparsely populated county and the roads are slow, so plan viewings carefully and ask for video first. Ponies raised in the Welsh hills are typically hardy, good-footed and easy keepers — which is a real advantage for a family on limited grazing, though it also means being careful about weight and laminitis once they move to richer lowland grass. Many are sold young or unbacked, so be clear about the level of schooling you actually need.