I like the sound of stoicspren, and stubbornspren, though it is a bit long. I think they might be named after their appearance, because there seems to be two patterns for naming, they are either named after an ideal, not the best word for it but can't think of anything else, such as honorspren, highspren, cultivationspren. The other pattern is they are named after their appearance, ashspren, inkspren, lightspren. So based off of appearance they could be named things like stonespren, moltenspren, these sound less likely but are still an option.
they bond lightspren, aka reachers