Here is a non-exhaustive list of current and past collaborators that I had the pleasure of interacting with, either on research papers or through other means such as project collaborations or students co-supervisions. I mainly list more long-term collaborations and more recent ones because older or more short-term ones I may have forgotten (and if I did, I apologize, and please drop me an e-mail with a reminder).
The more active collaboration institutions are also a good place for students to find internship opportunities or long term stays abroad.
Companies from industry are a bit more dynamic than academia, and thus are more prone to change their strategies and focus. Therefore, only very recent collaborations with industry can be counted as internship opportunities by students.