Potentially useful resources that I've collected over the years
Research
Databases
X-ray Spectroscopy:
X-ray Data Booklet - Binding Energies, Emission Energies, Subshell Cross-Sections, almost too much info to list
Center for X-ray Optics - X-ray Interactions with Matter (Transmission, Reflectivity, attenuation length, ect)
Crystal Structures:
Materials Project - Giant compendium of results from automated calculations (Band Structure, XANES, EXAFS) across crystal structures, as well as just a fast and easy place to spin around a crystal in 3D.
RSPt - Full-potential Linear Muffin-Tin Orbital, beyond DFT methods DFT+U and DFT+DMFT
Quanty - 2nd quantization multiplet code, written in C/C++, but has a scripting language written in Lua. It focuses on tools to solve the mathematics of quantum mechanics so you can focus on the physics.
X-ray Larch - Python based data analysis tool for processing XAS data with capabilities for visualizing multiple other types of spectroscopy (XRF, RIXS)
Chaotic Dynamics: An Introduction 2nd Edition, Baker and Gollub, ISBN-13: 978-0521476850
Theoretical Mechanics of Particles and Continua Dover Edition, Fetter and Walecka, ISBN-13: 978-0486432618 - Sounds scary, but is really just graduate classical mechanics
Nonlinear Dynamics and Chaos 2nd Edition, Strogatz, ISBN-13: 978-0813349107
Quantum Field Theory 1st Edition, Srednicki, ISBN-13: 978-0521864497
Quantum Field Theory and the Standard Model 1st Edition, Schwartz, ISBN-13: 978-1107034730
Many Body Quantum Theory in Condensed Matter Physics, Bruus and Flensberg, ISBN-13: 978-0198566335
Notes, Lectures, and Talks
David Tong Notes - Everything from Vector Calculus to String Theory
MIT Open Courseware - Recorded lectures on almost every possible topic, often with accompanying lecture notes, problem sets, and worked examples
Kevin S. Huang Notes - Slapdash of notes from various topics, as well as solutions to Townsend’s A Modern Approach to Quantum Mechanics
Research Experience for Undergraduates (REU) Applications