Notion is a flexible workspace combining notes, docs, databases and project boards, used by teams to centralize knowledge and manage work in one place.
Airtable is a spreadsheet-database hybrid that powers flexible project trackers, content calendars and lightweight apps, and serves as a backend for many no-code tools.
ClickUp is an all-in-one project management platform with tasks, docs, goals and dashboards, aimed at teams that want to consolidate many tools into one.