They sell them at my local food markets, and always labeled as "Ancient Sweets".
A new one for me is a yellow w/red stripes bell pepper, sold under the name of "Aloha Pepper." Thick walls, juicy, and I think even sweeter than the Ancient Sweets. Different though. They have only just begun to show up for sale in my area.
Have not tried to grow either from seed.
I think there is a thread here somewhere about trying to save seeds/grow out the striped bell peppers and as memory serves me, no one had luck getting a striped pepper. Must be a hybrid.
Any chance the Ancient Sweets might be either Joelene's Italian Red pepper, or Stocky Red Roaster? Fusion_power (Darrel) grows these and was the one to introduce me to them. Both great sweet peppers. Joelene's is a bit crinkled while Stocky Red Roaster grows with smooth walls.
You can read a little bit about them here:
https://www.wildgardenseed.com/index.php?cPath=80