WP Page Builder - A free, fast and intuitive WordPress page builder
Mobbin - Latest mobile design patterns & elements library
Elementor - Elementor is a front-end drag & drop page builder for WordPress.
pttrns - iPhone and iPad user interface patterns
Slider Revolution - Slider Revolution is more than just a WordPress slider. It helps beginner-and mid-level designers WOW their clients with pro-level visuals.
Page Flows - User flow design inspiration for mobile & desktop