Lubuntu is an official Ubuntu flavor which uses the Lightweight Qt Desktop Environment (LXQt). The project's goal is to provide a lightweight yet functional Linux distribution based on a rock-solid Ubuntu base. Lubuntu provides a simple but modern and powerful graphical user interface, and comes with a wide variety of applications so you can browse, email, chat, play, and be productive.
https://lubuntu.me/groovy-released/
https://lubuntu.me