Here are some neat tools that I think everyone who does math with LaTeX should be aware of:
A tool to help you find out symbols you need with just a rough sketch.
TeX Match https://github.com/mrbenshef/TeX-Match
Same as Detexify but this one is an open source offline desktop application for all 3 common desktop operating systems.
This is a full fledged text to LaTeX OCR service that lets you quickly convert images of equations to LaTeX code. Normal users get 50 snips for free per month, education accounts have 100. Alternatively, you can also use this open source application to call the MathPix OCR API directly, which allows you to make 1000 requests per month for free, but obviously this is strictly OCR, so you don’t get other fancy features as MathPix Snip.
Please share any more cool stuff and I might add them to the post later.