I could't figure out a name for this so we will just refer to it as Shirt Mesh 000. There's a female and male version of this mesh as I just needed separate swatch options for them. This really is just a slight edit of the Get Together "jersey" but made into a cotton tshirt and slightly elongated. As for swatch options, there are 19 for the girls and 16 for the boys.
Only for The Sims 4.