RedditSave is an app to download videos. With this app, you can get videos from Reddit without having to leave their browser or app. These are all embedded from Reddit in high definition (HD) quality. 

To use this extension, select the best quality videos from the posts, and save them to your device. Another option is to download them from the main page.

This extension is pretty easy to use, and there is no special configuration you have to do. It's compatible with most browsers, meaning you can use it with Firefox, Chrome, Safari, Opera, and more.