How to design your Arduino shield using Proteus - PCB Design Tutorial - PCBway
Arduino uno shield template Resources - EasyEDA
General purpose board using Arduino MEGA PCB template, with Arduino Nano controller board, LCD+Keyboard, DS3231 RTC, NRF24L01 radio, and DS18b20 temperature sensor - Share Project - PCBWay
Circuitmaker Make an Arduino Uno Shield Template - YouTube
How to make PCB Arduino Uno Shape - parts help - fritzing forum
Arduino Shield - EasyEDA open source hardware lab
Shield Base - Arduino Uno - Altium Designer - Parte 1: Esquema - YouTube