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

Zhilong He's CV
改自Deedy CV的中文简历,可附头像。
Zhilong He

Demonstration of Noto Serif CJK and Noto Sans CJK fonts
A demonstration of the Noto Serif CJK and Noto Sans CJK fonts, using XeLaTeX or LuaLaTeX.
LianTze Lim

Example exam paper
An example exam paper based on the exam class, which provides commands for:
creating regular, multiple-choice and essay questions;
showing answers for multiple-choice questions;
points per question counting.
This example was originally published on ShareLaTeX and subsequently moved to Overleaf in November 2019.
Uploaded from ShareLaTeX

Example using examdesign
An example exam paper using the examdesign class, which has the following features:
automatic generation of answer keys if needed;
automatic generation of multiple versions of the same test;
environments for constructing the most common types of test question: matching, true/false, multiple-choice, fill-in-the-blank, and short answer/essay questions.
This template was originally published on ShareLaTeX and subsequently moved to Overleaf in November 2019.
Uploaded from ShareLaTeX

Example of qtree package
A demonstration of the qtree package, by way of its documentation.
Source and further information is available on CTAN.
This example was originally published on ShareLaTeX and subsequently moved to Overleaf in November 2019.
Uploaded from ShareLaTeX

fontspec all the fonts!
A sampler of the OTF/TTF fonts installed on Overleaf that you can use with fontspec in XeLaTeX and LuaLaTeX, including for various scripts/languages.
LianTze Lim (Overleaf)

Annotated Bibliography Template
Simple annotated bibliography template, based on Lecture Notes in Computer Science bibliography styles.
Mohammad Reza Saleh Sedghpour

Academic CV Template
Template for an academic-style CV in the US, based on the Awesome CV template. Made for those in the biological sciences, but likely easy to adapt to other fields as well.
Jessica Rick

Espectro Trasladado de OFDM
Este gráfico muestra como cambia el espectro de una señal banda base de OFDM cuando es "trasladado" mediante una señal portadora de alta frecuencia. Para no representar el gráfico a una frecuencia de portadora determinada (f_C), la función ofdm(x) es "trasladada" a una razón de (f-f_C)/Rs de modo que la portadora esté representada a un valor cero. La imagen para esta figura se basa en la que aparece en la página 647, del texto "Digital Modulation Techniques, Second Edition" de Fuqin Xiong, editado por Artech House, Inc.
Ramón Jaramillo