Voice, YouTube, & occassionally Translate (sorry, your FOSS option doesn’t cover non-European languages well) are the Google servers I can’t quite shake. I almost never use the Voice account but when I do, it’s some required voice call from a US number for a bank or similar—which is very important, to make these calls, but it is so infrequent that I can’t justify paying for an entire service for 1–2 (usually very long) calls annually.