Search for “AG1 batteries” or LR621 or SR621 or even 364. They are basically all the same, the only differences would be substance inside the battery (lithium, zinc, silver, etc.)
Trust me, I keep a drawer full of batteries going from AG1-AG10, all the “normal sizes” (eg. AAA, AA, etc.) to the larger more well known button cells like CR2032, CR1632 and even weird ones like CR322 which is called a pin type or fishing battery.
Here’s a great reference regarding the AG1’s
https://www.batteryequivalents.com/364-ag1-lr621-sr621sw-battery-equivalents-and-replacements.html