From DD_Baumann https://twitter.com/DD_Baumann on Twitter: David Tong wrote some notes on particle physics and QFT using only high-school maths: https://www.damtp.cam.ac.uk/user/tong/particle.html?fbclid=IwAR18BiqwuDWvr4SNSZD7pXNLA33KcvtZEUuI48eTaE2Ms1k-C1GqbQhrDoY I haven't read it yet, but coming from David they are surely awesome.