I've found the Tweets from Dr. Eric Feigl-Ding useful to learn about the math behind how viruses spread
Helpful statistics on mortality rate by age group, sex, and pre-existing conditions
Well cited resource on quantitative and qualitative metrics
Well written blog post by Tomas Pueyo on the efficacy of starting "social distancing" as soon as possible. Being updated regularly.
Gabriel Goh created this epidemic calculator based on the (Susceptible, Exposed, Infectious, Recovered).
Round up of projects relating to COVID-19. Everything from grocery delivery to supply chain to ventilator production projects
Put together by one of my colleagues. There will be a severe lack of ventilators and volunteers are working on solutions that aren't fancy. They just need to work.