Browserify is extremely useful! I've mostly used it for cutting down on server side processing and for easily bundling code into nice little packages.
Its a nice little wrapper! I've used it for Discord bots mostly but it can be used for other things too like an online YouTube video downloader which I tried making but eventually gave up on.
Definitely the best web server module I have used for node. Its probably one of the modules I use the most! It can be buggy at times but most of the time, its all smooth!
Yarn is awesome! Since it uses its own servers unlike the normal npm, it is faster and you rarely encounter issues. Very helpful for building stuff taken from GitHub etc
Really an excellent library for mobile apps! The fact that it is web technology-based, but builds to native binaries means that you can leverage the best of both web and native worlds. Not to mention the fact that if you develop for Android and iOS, 99% of the time it works without any extra modifications. It really is awesome!
I absolutely love this library! Its great for making things like embedded code views, or just a really nice text editor. Its the backbone of one of my favorite editors, Visual Studio Code which makes it familiar to the average user.
Personally, I have used React more often than Vue, but I do have a few things to say! Vue is more lightweight than React, and is generally snappier. Its very useful at freshening up old sites that have been neglected for years and Angular just doesn't really cut it for me.
In the project that I am working on, the front end of the main website is built with React. I've been working on it for the last few months and haven't faced any major issues! React is much easier than any other front end library, also it is very popular and known by many so it is easier to find help resources and general support. Considering the fact that it is widely used, I'm also planning to use it in upcoming projects :)