You can never have enough white T-s. White T-shirts job is to fit perfectly and look effortless.
If you are looking for a casual tuck in - go for the V neck . For layering, look for the boy fit and make sure it’s your exact size otherwise it will bulk you up. I usually like to buy mine from :
1. @sunspelclothing specially for the boy fit Ts
2. @reserved T- shirt in organic cotton
3. @zara for scoop neck T-shirt
5. @topman I love their T-shirts although it’s for men but who cares