| Bundlephobia | Shows how much size is particular NPM package after including it in your bundle | Audit |
| CDN Finder | Show CDN used on website, easily visible | Audit CDN |
| Fontdrop | Optimize font by turning off features, visualization real time | Font GUI |
| Glyphhanger | Optimize fonts, subset | CLI Font |
| Google Devs Showcase | Google use cases of performance optimizations | Business Case Study |
| Google Webfonts Helper | Quickly download google webfonts in various variants and formats, with @font-face | Font GUI |
| GTMetrix | Tool for auditing website performance. Has waterfall | Audit Performance |
| Identifont | Visually compare two fonts and see the difference | Font |
| Imageoptim | Mac app to optimize your images | Images |
| Kraken | Compress bitmaps | GUI Images |
| PageSpeed Insights | Google lighthouse report | Audit Performance |
| Redbot | Audit headers and their syntax | Audit Headers Security |
| Remove BG | Remove BG from bitmap | Images Tool |
| Request map | Visualize request map to show how long are the request chains | Audit Performance Security |
| Request map | Show request map for the website | 3rdParty Audit |
| Sitespeed | Run your own scheduled performance testing and compare competitors | Audit Enterprise Self-hosted |
| SSL Test | Audit SSL parameters, warn about security issues | Audit Security |
| Subsetter | Subsets fonts online | Font GUI |
| SVG to PNG | The best tool to rasterize SVGs | Images SVG Tool |
| SVGOMG | Optimize SVG image with live preview | GUI Images SVG |
| Timeline Viewer | View and compare Chrome Devtools timelines to detect improvements and regressions | GUI Performance |
| TinyPNG | Compress bitmaps | GUI Images |
| Wakamai Fondue | Detect if your font is variable (can be bold/light without loading additional variants) | Audit Font |
| Webpagetest | Best waterfalls on the market. Blocking 3rd party (or any other resource) experiments. Comparisons of two tests (ie. before and after) | Audit Performance |
| Website Carbon | Shows how much carbon is generated to enter your website | Audit |
| WPO Stats | Business case studies of performance optimizations | Business Case Study |
| Yellowlab Tools | Very fast, easy to understand and actionable performance report | Audit Performance |