The list is a bit fragmented. It doesn't really give Nextcloud enough credit. Nextcloud can replace _most_ of google in one shot -- calendar, reminders, contacts, drive, docs, hangouts, maps, photos, and more (https://apps.nextcloud.com/). I think it's not as popular because 1. it's not free (as in beer, but it is free as in speech) and 2. it's kind of fiddly to get up and running. You can either host it yourself or sign up with a provider, but either way it's not super intuitive and nowhere near as polished as what we're used to these days. But, if you're looking to get off of Google and don't want to sign up for 10 different things, Nextcloud is worth a look.