SmallDevTools - Handy developer tools with a delightful interface
Talebook - Understand your client and kick-off your new project!
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
UXsniff - Track user behavior on your website and improve conversions with UXsniff: the user experience watchdog that looks out for you.
Profitable developer tools database - A database of 103+ hand-curated profitable developer tools
UserBit - A full-stack qualitative research platform for UX & product teams.