Understanding Arduino UNO Hardware Design - Technical Articles
Amazon.com: Arduino Solutions Handbook: Design interesting DIY projects using Arduino Uno, C and C++ (English Edition) eBook : Saini, Dr. Sandeep, Kaur, Manpreet: Books
Arduino Projects with Tinkercad | Part 2 by M.Eng. Johannes Wild - Ebook | Scribd
Circuit design software that makes it easy to design, document, and debug electronics projects for the breadboard (more info in the comments). Would you find this useful? (x-post with r/ArduinoProjects) : r/arduino
Arduino Introduction | Proteus Introduction | Design of an Arduino based circuit on Proteus - YouTube