An excellent tool for determining how to match fabrics across different lines is the bundles or sets section of many online shops. Not only is the shop showing you which fabrics can be mixed and matched but many times they also offer inspiration for potential projects! Here are some of my favorites. (Above, Summer Peony Fat Quarter Octet from Alewives Fabrics)
Summer in Pink 8 Fat Quarter Set from Flair For Fabric
Mornin' Sunshine! from Spool
A retro-look combo from Fabric Supplies
Baby Boy Quilt set from FabricWorm
Gingham and Animals Fat Quarter set of Japanese fabrics from Matatabi