This crochet size and weight infographic details all the different yarn weights and the specifics of each. It breaks down the yarn type, weight, wraps per inch and ply. This infographic also includes a chart of different crochet hook sizes.
Garment inspiration: An interesting, sleeveless cowl knit tube top one could wear with either end of the tube "up." It even has a halter-wear iteration. While labeled a DIY, it's just this series of s (Diy Ropa Patrones)