It's now very easy to add some Lottie animations to your website with Oxygen.
All you need to have is the plugin OxyExtras and some Lottie files (in JSON format).
Here is a list of some websites with free Lottie animations you can easily use with the plugin:
https://lottiefiles.com/recent
https://icons8.com/animated-icons
https://www.lottieflow.com/
https://useanimations.com/
https://dribbble.com/tags/lottie
Note that if you want to import JSON files in the Media library, you can use this plugin:
https://wordpress.org/plugins/wp-extra-file-types/
(Choose the JSON format file in the settings and enable to "Check only file extensions" option)