VILRITA's knitting yarn collection brings together a range of fibers and weights, from cozy wool and crisp cotton to soft acrylic and plush velvet, and most of it works for crochet too. Many are machine washable if the ball band allows.
Start with the weight your pattern calls for. If the pattern is a summer top, look at Alize Cotton Gold; if it is a plush blanket to sink into, YarnArt Dolce; if it is a baby garment, Gazzal Baby Cotton.
When substituting yarn, match the length per 100 g, then knit a swatch to check gauge.