These are helpful resources that I have used to learn more about electronics.

Resources for Learning Electronics

Books: 

History: Faraday Maxwell and the Electromagnetic Field, The Chip: How Two Men Invented the Microchip, The Forgotten Genius of Oliver Heaviside, Much Ado About Almost Nothing: Man's Encounter with the Electron

Theory: Purcell Electricity and Magnetism, Introduction to Electrodynamics (Griffiths)

EMI: Electromagnetic Compatibility Testing (Ott), Noise Reduction Techniques (Ott), High-Speed Signal Propagation: A Handbook of Black Magic

Circuits: Art of Electronics, Practical Electronics for Inventors, Operational Amplifier and Linear Integrated Circuits (Fiore), Microelectronics (Neamen), Microelectronics (Sedra and Smith), Linear Circuit Analysis (Davis) 

Power Electronics: Fundamental of Power Electronics (Erickson), Principles of Power Electronics (Kassakian)

Analog Design: Analog Circuit Design: Art, Science, and Personalities (Williams)

Controls: Control Systems Engineering (Nise) 

RF: The Electronics of Radio (Rutledge)

YouTube Channels: 

Learn Electronics: Ali Hajimiri (CalTech Professor), EEvlogs, bigclivedotcom, MIT OpenCourseWare, Neso Academy, Electronoobs, Ben Eater,  Mr. Carlson's Lab, Practical Engineering, Simply Electronics, The Engineering Mindset, Adafruit

Project Focused: GreatScott, William Osman, Joe Grand, Jeri Ellsworth, Louis Rossmann, James Bruton, Maker's Muse, PeterStripol, Marco Reps,  Zach Freedman, Carl Bugeja

Altium/PCB Design: AltiumAcademy (especially Eric Bogatin and Rick Hartley), Phil's Lab,  Robert Feranec

Controls: Brian Douglas

Forums: Reddit (/r/electronics, /r/electricalengineering, /r/printedcircuitboard, /r/ECE), EEVblog Forum