It'll be interesting to see if the FMA (big second-tier finance conference, hosts the "lower tier" finance job market) remains in-person (with a vaccination requirement) in October. That's the first big (1000+ attendee) in-person conference in economics that I know of.

Southern Economic Association also meets in the fall, IIRC in about November, but I think it would be smaller than a thousand participants. Traditionally it has included a few job market interviews for academic positions in southern schools. National Association of Business Economists (business and government people) has meetings too, but I don't know how large they would be.

Otherwise the other big economics meetings are international, such as Econometric Society. There's also European Economic Association, usually late August.

On the topic of econ conferences, one of the “allied social science” associations that hosts its own summer conference in addition to the winter AEA meetings announced today that their June 2022 conference is moving from Detroit to online. Seems a bit premature to me, maybe they were approaching a deadline to avoid/mitigate a cancellation penalty?