My go-to yarn for craft projects (usually on 7-count plastic canvas) is your basic medium/worsted-weight acrylic yarn. Red Heart is the standard, but there are a couple store brands that I also use: JOANN's Big Twist + Hobby Lobby's I Love This Yarn. Both are slightly softer than Red Heart, but my concern when choosing between the three brands comes down to color.
Lol- I made color charts for me to use at home to help plan out projects. Figured I'd share with others so maybe my weirdness can help you out too! Note from Kat: I linked to Michael's for Red Heart when color available because their everyday price is cheaper (when I typed this). But be sure to compare, because sometimes you can find them on sale for a better price.
Disclosure: Should you click on some of the links and purchase, I may be compensated (Lol- meaning in a few months, I might be able to afford a gallon of gas 😅). If there's a link, it's because I actually used or considered it myself for projects.