Visual Studio extensions I use
Feelgood
I’ll start with something that’s not even an extension. Far from necessary it’s still among the first things I install. The FiraCode font just makes everything look a bit better.

A small sample from some real code. Check out their website for all details and install instructions.
Code analysis
Roslynator is an extension that analyses your code and gives lots of helpful suggestions for improvement. Unfortunately it often have a lot of suggestions for code you get from external assets. To prevent noise from other peoples code I usually chose to only see messages for the current project or document.

On the theme of writing better code I also install the Serilog Analyzer that helps me get the most out of my goto logging framework, Serilog.
Tools
I’ve been using GitHub Copilot and Copilot Chat for a while now and find that they’re useful in many case. They don’t always write great code, or even working code, but more often than not they produce good code.
That’s it
I’m afraid that’s all I need for most cases. Mostly I think Visual Studio does what I want it for, and have everything I need and quite a bit more 🙂 So there’s not much need for me to install extensions.
But I’m sure there are great extensions I don’t even know about. Feel free to add your favorites in the comments.