for any tshirts (plain, pocket, graphic, etc.)

ysl.com

uniqlo.

thrift store always or ebay

Polo

Consignment or multi-brand retailer or thrift or eBay or depop or grailed for graphic

Plain at Uniqlo

I don't buy pocket t-shirts but D***ies and Carhartt are two of the most popular ones

Hanes, D***ies or Uniqlo for shirts that I'm just going to beat up

Don't have a go to for more quality stuff so would definitely like some suggestions regarding that