Elementor - Elementor is a front-end drag & drop page builder for WordPress.
Kodular - Much more than a modern app creator without coding
Layers - A simple Wordpress site builder & its free forever
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
OnePager - One page theme builder for WordPress
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.