LibreBVE is a project finding routes and trains that are under liberal licenses in order to make them available (maybe even in the core of the game? Who knows!)
The list is divided into two groups (besides routes / trains) - Ones that are very probably Libre and ones that look (and you have to do research).
https://github.com/joeyfoo/alstom-metropolis-for-openbve (Doesn't work properly on OpenBVE - maybe someone knows how to fix the cockpit?)
They are officially under a Creative commons license, but Creative Commons is a collection of licenses, and some are in conflict with each other. Will have to contact the creators and find out exactly.
* The 'Run' and compressor sounds for this locomotive are borrowed from the (similar) Class 47 for openBVE, and are courtesy of Martin Corbett of BVETMD
This needs to be fixed by looking for other sounds - similar
Probably only the sounds need to be replaced.
IF YOU HAVE ANY FILES ON LIBRE LICENSES, PLEASE FEEL FREE TO SHARE. MAYBE AN OFFICIAL LIST SHOULD BE MADE