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Some of the packages of CTAN are really good but not discovered by many. I recently encountered one of the good ones, namely latexindent, and I thought that would be great if everyone introduces the best he/she is aware of. So,

Kindly please introduce what you found useful in CTAN that should be recommended to others.

marked as duplicate by nidhin, CarLaTeX, Mico, David Carlisle, Skillmon Dec 13 '18 at 18:01

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