I would like to know if there is currently a database of video-clip and / or images depicting virtual agents expressing emotions. I've searched everywhere, but I have not been able to find it...
For the work of my master thesis (back in 2011) I needed an expressive virtual character, but like you I couldn't find anything, so I decided to create one myself.
I found the Daz3D Studio, which is free to download and use, but then every element you use you need to buy it, with the oldest models becoming free after some time.
So I installed the studio, found a free female model (back then it was Victoria, now I found Genesis, check links below), and so far I didn't pay for anything.
Eventually when I wanted to manipulate the facial expressions of the virtual character (model) I had to buy a relevant package and paid about 20$, which I see is still priced about that.
I am not an expert in 3D graphics, I only had a small experience, and to be honest in the beginning I found the interface a bit confusing, so it took me a couple of weeks to manage to create the expressions, but for me at that time it was the only solution.
Since I was already familiar with this method I did the same for a conference paper back in 2016.
Hope that helps! Good luck!!
Thesis Facial-gesture Based Interaction with Expressive Virtual Characters
Conference Paper Preliminary Evaluation of a Web-Oriented Assessment Tool for...