Meteor Client’s community on (over 150,000 members at its peak for 1.16.5) was a bustling hub of config sharing, add-on development, and drama. The client’s open-source license (GPLv3) encouraged forks like Meteor Rejects (adding more “cheaty” modules) and Meteor++ (performance improvements).
Meteor’s combat system is designed around "crystal pvp" and "anchor pvp," which were the dominant meta in 1.16.5.