It's not clear what exactly you are looking for, but we use Zoom at work. https://zoom.us/ Zoom does have a free version that is fairly robust but it is often used for telehealth purposes. It is HIPAA compliant and very secure. They have apps as well as a pc-based version. I highly recommend Zoom.
Didn't even know that Signal offered video chatting, but isn't the problem that most people are using Skype? We need to have tools that work together, but now that I think of it, it's probably not possible.
