[kimos]

My brother in size Small-Tall, tell me where you shop!

This is a good one: https://tallslimtees.com/

I also do some made to order from Son of a Tailor and Proper Cloth, but it’s expensive and laborious and slow and risky.

[overgard]

Dunno if it's the best brand in terms of bang for your buck, but I've bought a lot of shirts from "Have it Tall" on amazon and I have zero complaints about the fit. 6'4" and a pretty average build.