Using DuckDuckGo to search both social and “print” media would probably find you more virtual places where other interested parties hang out. There might be others who inhabit virtual worlds like SecondLife but you’d have to signup and login to find them, if they declare their qs interest.
Through my work, I came across QS (this forum) but have been engaged with ‘data nerd’ type findings my entire life. Reddit has a few subs that really contribute to understanding your data, and data in general like:
r/dataisbeautiful
r/datavisualization
r/quantifiedself (no affiliation to this forum, but has some overlap of audience members)
I started my journey using a daily diary journal app - Daylio. It’s actually a big influence on what I do for work now and shows in the designs I build for our developers. The nonprofit I work at is building a QS-inspired mobile app and web app that acts as a “business analytics dashboard for a person,” if that can be said.
You’ll find bits and pieces of QS in chronic condition patients, their affiliated organizations, and other similar entities. However, they are not necessarily going to say “quantified self” versus just report on their symptom and health tracking.
For example, my mother spent years changing her diet and lifestyle routine to manage her multiple sclerosis. It took literal years of pen to paper note taking and manual comparisons (before the time of mobile apps doing this for us). She would have no idea what someone is talking about if they said quantified self, but certainly would hold a conversation about methodology and findings otherwise.