Here are some commonly unknown WordPress functions I've come across when developing with WordPress. A few little gems that I wish I discovered long before I needed them.
WordPress Gear is a “compendium” of useful developer tools for working with WordPress. I like what I see. h/t @paul_wp
Curtis McHale has written a nice three part series on WP Lift offering a guide to pluggable functions in WordPress. For those unaware, pluggable functions make it easy for other developers to override your functions in their own plugins and themes.
Jetpack and WordPress.com can publish to Telegram. The ultimate gitignore for WordPress projects.
Transients are an excellent way to speed up complex queries in WordPress. Dave Clements shows you in this post how you can use transients to avoid bringing a site to its knees like he did, by caching those queries instead of repeating them on every page load.
Drew Jaynes hast started a new website called Filters of the Day with the goal of documenting 3 filters a day for the next 365 days. I’m sure this will be a great opportunity for us to learn more about the various filters available to us in WordPress.
The WordPress REST API is at a bit of a crossroads. There is a proposal on the table by the core team of four contributors — Ryan McCue, Rachel Baker, Daniel Bachhuber, and Joe Hoyle — to ship endpoints to WordPress core iteratively. There is a pushback on this proposal by WordPress Project Lead and co-founder Matt Mullenweg.