In WordPress codebases, we mostly follow "The WordPress Way" through the WordPress Coding Standards and Gutenberg project rulesets, with a few exceptions and additional expectations for our company projects.
This reduces context-switching, increases our ability to hire engineers familiar with WordPress' standards and leans on practices and code proven to work in WordPress over time and scale.
We work with other software including Laravel, Gatsby, node, bash and serverless functions.
In these projects, we follow different standards for PHP and JavaScript.
To that end, we have some general best practices for HTML, CSS, PHP and JavaScript.