We're probably a little bit too early to be focusing on these things. Not sure if we actually need a symbol for every bitcoin denomination, but if we would, It'd probably make more sense to focus on bits and mbits first. We're probably a long way of seeing things priced in sats.

Anyway, someone proposed a symbol for sats on Reddit a year ago:


https://www.reddit.com/r/Bitcoin/comments/8xcy81/introducing_a_new_symbol_for_satoshi/