Here is a list of interesting conferences (with a focus on IO and theory). They are ordered by the submission deadline.

Conference Dates Location Submission
IIOC May 1 - May 3 Philadelphia 29.01.20
World Congress of the Econometric Society Aug 16 - Aug 21 Milan 31.01.20
OLIGO Workshop June 4 - June 6 Maastricht 31.01.20
GAMES July 13 - July 17 Budapest 02.02.20
EEA Aug 24 - Aug 27 Rotterdam 15.02.20
Midwest Economic Theory May 1 - May 3 Greenville 15.02.20
Verein für Socialpolitik Sep 27 - Sep 30 Cologne 01.03.20
EARIE Aug 28 - Aug 30 Bologna 17.03.20
CRESSE June 26 - June 28 Crete 20.03.20
Contests: Theory and Evidence June 25 - June 26 East Anglia 01.04.20
Stony Brook International Conference on Game Theory July 20 - July 24 Stony Brook 15.04.20