Sketchfab is a large collection of 3d models you can access online. There are over 150,00 Creative Commons free models, most of them free of charge.
To access Sketchfab visit sketchfab.com and create a free account
You will then need to navigate to https://sketchfab.com/settings/password and copy the API token
In E-Learning Lab in the 3d Env or Objects tabs on the Assets section, click "Search Sketchfab". This will open a Sketchfab Browser.
In the window that pops up, just paste your API token and click "Save Token" to get started
You can then search for any model you like. When you click "Download" it will download directly to the Asset browser, where you can add it to your Project