Evernote Sign Up Page
Sign Up Page. Instead of the homepage it talks about its existing customers on this page.
Trello login page uses similar graphics as the home page to create a familiar sign in experience
Since Datadog is an enterprise product, it requires you to specify organization name during signup. Even for Google SignUp they require organization name and once provided, you can continue signing up ...
Zapier has an interesting Sign up page where they have deep integrated Google sign in to autoselect signed in user so it takes only one click to sign in.