Links that I follow:
(1) Operator Theory Information Network: https://operatortheory.org
(2) Operator Theory talks for early researchers: https://www.sites.google.com/view/otter-math/home
(3) Operator Theorists and Operator algebraists in India: https://www.jnu.ac.in/Faculty/vedgupta/op-alg-n-theo-india.html
(4) An international directory: https://operatoralgebras.org/directory.html
(5) Webinars in Operator theory and Operator Algebras (WOTOA).
Interesting articles that I have come across:
(a) A brief history of Operator Theory by Evans M Harell II.
(b) Slides on RKHS in Machine Learning by Arthur Gretton.
(c) A nice blog by Il Shan Ng on RKHS and Machine Learning.