I can say that Tandem is the one which strikes me the most. I had a privilege to test the product in early beta and you can see the benefit of such solution. Basically Discord for work which I believe will be adopted soon by many companies.
This was very confusing for me since I use Discord only for chat for various open source projects.
Tandem is voice and video chat - the part of Discord I never use.
Once you have a SINGLE full-time remote employee your team should operate as a fully-remote team. That means online meetings, online communications, documentation, etc.
https://insideremote.io/episodes/episode-2-power-of-synchron...