DownGit
Download a github repository or its subfolder.
You may try this if you are in China mainland.
Explainshell
Explain flags of common used shell command.
LatexDiff
Show the different of two versions of tex in PDF format. Better than any PDF-compare software due to the comparison on the raw level.
Snipaste
The best screenshot software. The Paste as Image window function is now an indispensable part of my workflow.
Mathway
It can solve the equation in chat style.
CheckLatexIEEE
It is an official IEEE website to validate your LaTeX tar file.
Detexify
It can recognize the symbol your draw and return the latex code for creating it.