ICT4D

Ona.io Open source, A+ Offline web & Android data collection software that we've used extensively. A modern fork of Formhub, from the same dev team.
Principles for Digital Development 9 principles to guide the implementation of information and communications technology for development (ICT4D) projects. If you're around DC, try to make the events in person.

Productivity

Pocket Save links to read later offline. Works seamlessly on iOS & Android. I literally use it every day.
Trello A great way to organize your ideas into boards, cards, and lists. For personal use and small projects, I prefer it to Asana.
worldtimebuddy The most intuitive time zone scheduler for multiple time zones. I use it every week.

TED Talks

The big idea my brother inspired Jamie Heywood, founder of PatientsLikeMe, shows how it's possible to crowdsource information about effective treatments of chronic conditions when patients share their data freely with the open data community.

Web Dev

Github Pages A great place to host Jekyll or other websites that don't need an application server. No hosting costs at all! This site is hosted on Github Pages.
Jekyll A fantastic static site generator that I use to power this website. Integrates nicely with Github pages. I've used it to build websites for USG, and was inspired by this Devseed article.
Sublime Text Hands down my favorite text editor for coding. Hundreds of free packages are available to facilitate coding with any language, and boilerplate for frameworks like Bootstrap.