This is a compilation of links that I believe might be helpful to budding (function-theoretic) operator theorists:

1. OTTER - Operator Theory Talks for Early Researchers
2. FOCAHA - Forum of Complex And Harmonic Analysis
3. Complex Analysis Lab
4. Focus Program on Analytic Function Spaces and their Applications
5. Operator Theory Information Network

Here are some lecture notes and expository articles on some topics related to Operator Theory that one may find useful:

1. Lecture Notes on Reproducing Kernel Hilbert Spaces by Vern Paulsen
2. Lecture Notes on Hardy Spaces by Benjamin Eichinger
3. Lecture Notes on Functional Analysis and Operator Theory
4. A survey of Drury Arveson space by Michael Hartz
5. A survey of Model Spaces by Stephan R Garcia & William T Ross
6. A survey of Dirichlet Space by Nicola Arcozzi, Richard Rochberg, Eric T Sawyer, and Brett D Wick
7. Lecture Notes on Clark Measures
8. Pick’s Theorem-What’s the Big Deal?
9. Lecture Notes on Spectral Theorem for Normal Operators
10. What does the Spectral Theorem Say? By Paul Halmos