Google Calendar - Spend less time managing your day & more time enjoying it
SmallDevTools - Handy developer tools with a delightful interface
Mixmax Calendar - The fastest way to schedule meetings with anyone, anywhere
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Sunsama - Calendar and scheduling for teams
Profitable developer tools database - A database of 103+ hand-curated profitable developer tools