Fossify Calendar★★★★☆Basic calendar app that works with your phone’s local calendars. You can do all the usual things you want to use a calendar for on your phone. Doesn’t clutter up your schedule with ads or vacuum up your personal data.
Microsoft Outlook (Android)★★★★☆It works. More stable than the desktop version. Handles mail, calendar and contacts, offers the focused/other inbox view. Tries to keep you in Microsoft’s apps. OK for work, wouldn’t use it for personal mail.
Microsoft Outlook (Desktop)★★★☆☆I won’t say I’ve never liked Outlook, because the macOS version has been pretty decent for a while now (if a bit of a resource hog), but the Windows versions have always been awkward, cluttered, and quirky.
Nextcloud Calendar★★★★★Self-hosted, web-based calendar that syncs easily with other apps and has completely replaced Google Calendar for me.
Thunderbird (Email and Calendar)★★★★★Stable, capable desktop email application, works well with multiple accounts including Gmail, Nextcloud, easy to set up and use but with advanced settings when you need them. FLOSS.
Vivaldi (Web Browser)★★★★★Spiritual successor to the original Opera browser, this ultra-customizable web browser can open into a full suite for email, calendar, feeds and more – but only if you want it to.