"Best" is subjective but how about "still popular"? So here's a list of the 31 most visited articles in the past year in reverse chronological order of publication.
(31 as the number of days in December)
Anything catches your fancy? Want to write an update for 2022? Please do, but check with the original author first to give them the right of first refusal.
- Progressive jpegs: a new best practice
- Using NGINX, PHP-FPM+APC and Varnish to make WordPress Websites fly
- Deciphering the Critical Rendering Path
- A Tale of Four Caches
- Prefer DEFER Over ASYNC
- Testing with Realistic Networking Conditions
- Loading web fonts asynchronously
- Speed Versus Speed to Market
- HTTP/2 Push: The details
- Evolution of : Gif without the GIF
- 3 Tips for Faster Font Loading
- Tracking CPU with Long Tasks API
- SQIP – Vague Vectors for Performant Previews
- Progressive Image Loading using Intersection Observer and SQIP
- The unseen performance costs of modern CSS-in-JS libraries in React apps
- Self-hosting third-party resources: the good, the bad and the ugly
- Native Image Lazy Loading in Chrome Is Way Too Eager
- Reading a WebPageTest Waterfall Chart
- Performance Tips for Background Video
Latest edition, 2020, is too recent and therefore excluded, but if you're curious, this "No JS" one is the most popular and by an order of magnitude, no less.