Here is a list, as best as best I can recall:
Texas – ConDFW, Fencon (both Dallas), Armadillocon (Austin), Apollocon (Houston), AggieCon (College Station), Lone Star Con 3 (San Antonio).
Oklahoma – SoonerCon (Oklahoma City), Conestoga (Tulsa).
Missouri – Archcon (St. Louis), ConQuest (Kansas City).
Colorado – GalaxyFest (Colorado Springs).
Illinois – WindyCon (Chicago).
Ohio – Marcon (Columbus).
Oregon – Sasquan (Spokane).
Pennsylvania – Philcon (Philadelphia).
Tennessee – Libertycon (Chattanooga).
Virginia – Ravencon (Richmond, then Williamsburg).
Conventions I received invitations to but were unable to attend include DragonCon in Atlanta, ContraFlow in New Orleans, LonCon 3 (London) and MystiCon (Roanoke, Virginia).
In the case of DragonCon, bad weather plus bad luck on the highway made me have to turn around in 2017. Contraflow was stymied by car troubles. I could not make LonCon because the newspaper where I worked was sold and the new asshole owners would not honor my previously accumulated vacation time. Mysticon was a problem with time and money.
Some of these cons have already passed into history, like Conestoga and Apollocon, both which were great fun the years I attended.
I’ve always felt the volunteers who run such conventions are dedicated and self-less, and deserve much thanks for what they do that is such fun for others. I would never be able to do it myself.