"Every new app we build has a lot of things invented or code before. Buttons, hamburger menus, data entry fields might have a different color and shape, but in the essence they all have very similar characteristics. So why design them from scratch? Whether you need a splash screen or mobile list UI design, check out the pattern libraries offering ones in all shapes and sizes.
https://www.ego-cms.com/post/10-greatest-mobile-ux-ui-design-pattern-libraries-for-creating-a-better-app"