Jpeg.io - Convert any major image format into a highly optimized JPEG
compressor.io - Compress and optimize images.
Website Planet provides a good compression tool.
Any API - a full list of 275 Public APIs.
Rapid API has a huge marketplace of APIs.
Better Error Pages - a tool for making error pages.
OverAPI - collection of cheat sheets
BuiltWith Technology Lookup Find out what a site is built with and runs on
A great list of Web Development Tools on the David Walsh blog.
Graphic Design and Photo Tools
Polarr create a great Online Photo Editor