The Cost Of JavaScript
https://medium.com/dev-channel/the-cost-of-javascript-84009f51e99e

Priority Hints
https://github.com/WICG/priority-hints/blob/master/EXPLAINER.md

Resource hints
https://css-tricks.com/prefetching-preloading-prebrowsing/

air/shots
https://airbnb.design/airshots-discovering-a-workflow-for-app-screenshots/

Measuring the Real-world Performance Impact of Service Workers
https://developers.google.com/web/showcase/2016/service-worker-perf

Front-End Performance Checklist 2018 [PDF, Apple Pages]
https://www.smashingmagazine.com/2018/01/front-end-performance-checklist-2018-pdf-pages/

Client hints
http://httpwg.org/http-extensions/client-hints.html

Variable fonts
https://medium.com/@clagnut/get-started-with-variable-fonts-c055fd73ecd7

Perf mertics
https://www.smashingmagazine.com/2018/01/front-end-performance-checklist-2018-pdf-pages/
https://sites.google.com/a/webpagetest.org/docs/using-webpagetest/metrics