in the "with background" pack, there were a few symbols folders that were duplicated (due to a naming error) and those duplicated ones contained backgrounds when they shouldn't have. I removed the duplicates. Now all the of symbols should be background-free.
On the "with background" pack, I've made the symbols without a background as Wonderdraft does not currently support sample_color with symbols. thanks to u/GustavoMalek from reddit for pointing that out