I use Google Meet for my business which is essentially Google Hangouts, Zoom for doing some of my interviews because it works so well offering local recordings very easily, Zulu for making calls via my FreePBX system at the office (it’s for Sangoma FreePBX only) and Jitsi for personal use. There is also https://github.com/LubosD/twinkle which is an open source SIP tool that I use if I have to test SIP services.