Fiddler - Fiddler is a debugging program for websites.
Reminder Commander - Reminder manager that reminds you about important events in advance.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
Date Reminder - Date Reminder reminds you of recurring or nonrecurring events, like birthdays, bills to pay...
HTTP Toolkit - Beautiful, cross-platform & open-source tools to debug, test & build with HTTP(S). One-click setup for browsers, servers, Android, CLI tools, scripts and more.
Scheduled tasks - GNOME GUI for configuring a users' cron (automatic jobs). Some of its features are: