Grabin is brand that sells comfortable T-shirts with a sporty aesthetic. You can get all sorts of colours with this brand, everything from bright reds, blues to to whites with smart navy blue stripes on them across the chest! You can even find really great collared and semi buttoned T-shirts with them (somewhat like Polo T-shirts). All of this will only cost you INR 350 and up.
We personally love the collection of plain coloured t-shirts they have; and the one we most, most love is their melange grey t-shirt, a for sure classic, and needed staple. Plus most of them are made of cotton blends and you can buy them in the shop section of LBB.