Hoop Jones designed 6 beautiful desktop screens for a signup flow to onboard users in step-by-step process. Free to download in Sketch file format.
Freebies tagged signup
A tutorial about creating some pricing tables animating into a sign up form. Created by CodyHouse.
Animated sign up tables
Here is a set of 7 sign in screens for mobile apps. Free PSD created and released by Deividas Graužinis.