For a change of pace substitute other herbs for the basil, such as cilantro, mint, or even use bitter greens such as arugula, beet greens, or kale. Any green you can pulse and get to the same consistency will work. Pesto can be frozen, try freezing it in ice cube trays, then removing the cubes and storing in a ziplock bag. The pesto will stay fresher and you can just defrost as much as you need.