I’m not sure if they ship everywhere, but my favourite high quality ethical brand is AYM Studios. They’re based in the UK, and their tops in particular are excellent quality. Their stuff is usually double layered sustainably sourced bamboo fabric and they are incredibly supportive to the point I can happily wear them without a bra. The double layering also makes them an excellent choice for cold weather. I currently have 2 of their short sleeve fitted t shirts, a wrap top, 2 long sleeve crop tops and I’ve just ordered a new turtleneck they’re taking pre orders for.

Their styles definitely won’t be for everyone though as they’re all very fitted designs. For loser fits I’d also recommend Organic Basics, Everlane and Uniqlo.