Hello DOTLR,
welcome at Stridaforum 
I was confused first, so I’ve edited your subject line, please pardon me.
You’re looking for tires (tyres), note that you should use the ETRTO size 40 - 254 too,
perhaps you get better local search results then.
I do agree that matching tyres are still hard to find - therefore, I’m afraid, you don’t have much chance to choose the brand 
https://www.monsterscooterparts.com/144tire-tube.html
https://www.edinburghbicycle.com/kenda-slick-tyre
Good luck,
Chris