Apify is a web scraping and automation platform that let’s you extract data from nearly any website.
Measuring your site performance online (Digital Inspiration)
Qtmetrix.com is a detailed tool for measuring your site performance online (Digital Inspiration)
online image compression web app (squoosh.app)
squoosh.app is a free, online (and offline) image compression web app and laboratory that lets you tweak many aspects and make comparsions before you render out.
Quickly create complex and innovative data-driven Apps (Qlik Playground)
By accessing public data sets (including your own GitHub or Spotify data) through Qlik Associative Engine and APIs, you can experiment and create beautiful visualizations and data-driven apps using powerful search, data retrieval without writing queries, out-of-the-box charts with a single line of code and more. Free. Qlik Playground
SVG based web UI design tool (Figma)
Figma is more a web UI design tool than an SVG editor, but it has an excellent toolset and produces well-optimized SVG code. Free.
Auto-Hiding Navigation in CSS and jQuery | CodyHouse
Responsive Image Breakpoints Generator
TestMyCSS.com
Link: TestMyCSS.com
Page Analytics (by Google)
https://chrome.google.com/webstore/detail/page-analytics-by-google/fnbdnhhicmebfgdgglcdacdapkcihcoh