I’m always surprised by the number of knitters that I run into who don’t have stitch treasuries. I use mine more than any of my other knitting books. I have A Second Treasury of Knitting Patterns by Barbara Walker.
They’re quite inspiring. My book is loaded with sticky notes that have ideas jotted down for projects, notes on modifications, or rows converted to in the round. I love playing around with stitch patterns when I don’t know what to knit.
A stitch treasury is handy even if you aren’t doing design work. Sometimes I use mine to make simple things like cowls in an all over stitch pattern. You could also use them to replace a panel or stitch pattern in a pattern with something that is more to your taste. Like wise, you can use a stitch treasury to find a stitch to jazz up a plain pattern like a basic beret. It’s an easy way to spice up your knitting.