For me it’s Whatsapp. Like 99% of people i know use it so yeh… i still need it. I am considering moving the Whatsapp Gdrive backup to a local backup btw.
Google photos is also a major problem for us. We have a lot of stuff that want to migrate to different service (or store locally).
I still have a Google account (down from four). But in the past, I used this for literally EVERYTHING ; now I only use it for a couple of incoming, remaining emails. Posteo is my email and calendar today. That’s a big step already. Same with google maps: ive switched to other European providers, but occasionally i may still use Google Maps. I canceled Meta completely, no more FB, IG or WhatsApp; instead I use the fediverse alternatives, and SMS or signal for messaging. Lemmy instead of Reddit. I use a hard drive for storing files; I have nothing anymore in a Cloud, but sometimes colleagues force me to use Google Drive. Overall I’m pleased; Perhaps it’s not about canceling everything consistently, but a 95% reduction is a good initial achievement.