sip24.pw - great service, invite only.
narayana.im - good service, a bit expensive (about $.42 / minute). lets you know if your account is 'under investigation'... interesting.
spoofwave.com - cheap ($.10 / minute), has many issues, but overall is decent and has a nice support team.

All of these accept payment in crypto and are not KYC.

You can use programs like Zoiper5 to connect to your sip and start making calls.