Pie Register Premium is a robust WordPress registration plugin offering an array of features for user registration, login, content restriction, and more. Here's a breakdown of its key features and add-ons:

Free Key Features:

• Drag and Drop Form Builder
• Front-end User Profiles, Registration, and Login
• PasswordLess Registration
• Advanced Fields and Conditional Logic
• Redirection after Sign-up and Login
• Verify and Moderate User Registration
• Spam Protection and ReCaptcha
• Payment Gateway (PayPal Standard)
• Content Restriction and Custom User Roles
• Data Import/Export and Profile Picture
• Email Templates and Automation
• Invite-Based Registration
• Admin Helper Application and Shortcodes
• Developer-Friendly with actions and filters

Premium Key Features:

• Unlimited Registration Forms and Advanced Fields
• Role-based Redirection and Timed-form submission
• Auto-login after Registration and Global Content Restriction
• Invite through emails and Track user Invitations
• Multiple Payment Gateways (PayPal Subscriptions, Stripe, Authorize.net)
• Customizable Login Security (hCaptcha, Honeypot)
• Ticket-based Support

Add-ons:

• PayPal Subscriptions, Stripe Recurring, Stripe One-Time, Authorize.net (Payment Gateways)
• Social Login (Facebook, Twitter, Google, LinkedIn, Yahoo, WordPress)
• MailChimp (Email Marketing Integration)
• Twilio (Two-step Authentication via SMS)
• Profile Search, Geo Location, Bulk Email, Field visibility
• WooCommerce (Integration with checkout, login, and registration)
• bbPress (Integration with user profile and edit functionality)

Integrations:

• PayPal, Stripe, Authorize.net, Twilio SMS, Mailchimp
• Page Builders: Elementor, WPBakery Page Builder, Divi
• eCommerce: WooCommerce

This plugin caters to various needs, allowing for intricate user management, content restriction, payment integration, security measures, and seamless integration with popular third-party applications, page builders, and eCommerce platforms.