I have seen a few people doing this so I guess it's my turn. Here is a list of # I'm interested in.

Science:
#CellBiology
#MembraneTraffic
#MechanoBiology
#DevBio
#Growth
#Evolution
#Morphogenesis
#Microscopy
#ImageAnalysis
#BioPhysics
#Modelling
#SoftMatter

Other fields I am curious about:
#Epistemology
#HistoryOfScience
#SocialSciences
#GenderStudies

Fun&Games:
#Fantasy
#SciFi
#VideoGames
#BoardGames

I also love #SciCom and I'm always looking for new channels to communicate science.
Currently, I mainly use #SkypeAScientist, dedicated #Discord servers, and help when my institute organizes events.