Even the synthetic ones are great. Your options for colors are a bit more limited but the quality is still good. Would still recommend those over Bombas. I was disappointed in the Bombas quality and found myself having to buy them more often due to wearing down quickly.
Ultimately I hope you can find what you need! All the best to you, friend!
That is what this particular type of furnace is called in glassblowing. A glory hole is a specific furnace for reheating glass that has been gathered to keep it at the right temperature.