Xfce - Xfce is a lightweight desktop environment for UNIX-like operating systems. It aims to be fast and low on system resources, while still being visually appealing and user friendly.
Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.
LXDE - Why will you like it? Less resource needs. You can use it on your less-pricey embedded board or salvaged computer. Component-based design. Don't want something in LXDE, or you don't want to use LXDE but only part of it?
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
KDE Plasma Desktop - Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.
Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.