You can use other fats rather than just butter when making your pie crust recipe. It could be all one type or a combination of butter, vegetable shortening (like Crisco), lard (many people's choice), or something else entirely. I've seen recipes with coconut oil (to make it vegan), and I've used rendered beef or chicken fat on occasion (for savory pies). The main difference is that an all butter pie crust has the best flavor while providing a tender, flaky texture. Shortening doesn't add flavor, but allows the crust to hold its shape better, which is good for fancy crimping. If you do want to use something other than butter, the good news is that it's a 1 to 1 swap for any other type of fat you'd like to use.