Point "Create a Site" Links to Your Own Signup Page
Replaces the network's default wp-signup.php address in links and redirects with a custom page, such as a pricing or onboarding page, while keeping the real signup form available.
Snippet Library
Multisite snippets for WordPress
Snippets for WordPress Multisite networks: network-wide settings, new site defaults, super admin tools and cross-site tweaks. For network administrators who manage many sites from one install.