I found canning lids on Uline! If you follow the link below, scroll all the way down to the bottom of the page, and they’re under the “Replacement Lid” section. So far I haven’t had any issues with the lids.
I found some in Indianapolis in July at Meijer on the north side of town. Yesterday I found one box of small mouth Golden Harvest lids at Walmart in Saraland, Alabama and then 5 boxes of large mouth lids at Tractor Supply. I can find nothing anywhere where I live in Pensacola, FL.