Frontend web developer meetup, Newcastle upon Tyne
BangPypers
Python Meetups | Worldwide
Association of Teachers of Mathematics
List of Data Science Meetups Worldwide
Silicon Valley Startup: Idea to IPO
Data Driven NYC | 17k+ Members
SF Data Science | 15k+ Members
Blockchained India
List of Some of the Big Meetup Groups Worldwide
New York Open Statistical Programming Meetup | 10k+ Members
Data Science Festival - London | 9k+ Members
Greater Boston useR Group | 3k+ Members
Bangalore Ruby Users Group