My first horse was a clyde/Morgan. You could fit an entire family on her back. Someone bred her to an appendix. Twice. By all accounts, they liked the babies, but it was so weird to me.
There was a zoo back home that also bred horses. He actually stood a couple lovely performance based stallions, and quite a few people used them. One of the crosses he regularly did, and to great success was Newfoundland Pony mares to his Anglo Arab stallion. Typically came out as large ponies, with a flat kneed hunter trot to die for and a cute as pie jump.
Many of them qualified and competed at the Royal, no small feat for Nova Scotia riders, and a fair chunk of them were sold down to the States.
My barn owner when I was a teenager bought one, because he wanted a newfie pony. She was an incredible mover, super smart, and could have been so fancy. He left her to rot in the field, she foundered and last time I saw her, she was 15yrs old and looked like a workhorse on pony legs. I was furious at the waste.