I disagree with nearly this entire post, which is fun. I find that the poly blend shirts that the author loves (especially like the MongoDB shirt) are clingy and sweaty. Softness is low on my list of shirt priorities - comfort and fit are high. I don't know how you could see "mongoDB" and not think it is tech, but maybe I'm too mired in tech to have an outsider's perspective. Also, that dark heathered grey color is everywhere in tech shirts right now and it just screams tech. The only one of these with a good design is the Altibase shirt, but it suffers from having the ugliest color.
Give me black, 100% cotton, heavyweight Hanes Beefy-Ts with retro-looking logos.