Examples of powerful LaTeX packages and techniques in use — a great way to learn LaTeX by example. Search or browse below.

Polyphonic or Instrumental Music with M-Tx and MusixTeX on Overleaf
This example demonstrates how to write polyphonic or instrumental music on Overleaf, using M-Tx (.mtx) syntax.
This was made possible with a custom latexmkrc file. The music piece examples here were taken from the M-Tx documentation.
LianTze Lim

Formatação básica Fatec, Estrutura de Arquivos
Um modelo, com capa, e artigos, desenvolvido para todos os alunos, ou não, que desejam um arquivo simples de se usar.
Rodolfo Fonseca

Brown University Letterhead - Example Letter
This is an example letter to illustrate the use of the brownletter.cls LaTeX class file.
Copyright 2003, (tatbul@cs.brown.edu)
For more Brown University LaTeX resources, please see: http://cs.brown.edu/about/system/managed/latex/
Nesime Tatbul

Trabalhos acadêmicos FAESA
Modelo para trabalhos acadêmicos da FAESA - VITÓRIA ES
Victor Salles

Estilos para escrever Código Fonte em \LaTeX
Estilos para código fonte para Java e R language!
Taciano Morais Silva

Figures TIKZ du cours "L'effet Doppler"
Figures TIKZ du cours "L'effet Doppler" disponible à l'adresse : http://femto-physique.fr/optique/doppler.php
Jimmy Roussel

Example: Chess with TeXmate
Example: Chess with TeXmate
TeXmate

Beautiful curved grid?
A variant and a combination of Hering's and Zöllner's illusion. The red grid is completely straight all the time.
Submitted as an answer to the Showcase of Optical Illusions question on TeX SX.
Click the Illusions tag below to see more!
OSjerick

They are or not parallels?
The perpendicular lines that do not match row to row create an illusion of the lines between them being not parallel.
Submitted as an answer to the Showcase of Optical Illusions question on TeX SX.
Click the Illusions tag below to see more!
OSjerick