In no particular order
- Versioning
- Sidebar.io
- CSS Tricks
- Smashing Magazine
- Front End Front
- JavaScript Weekly
- Responsive Design Weekly
- Dev Tips
- CSS Weekly
- Web Development Reading List
- A Drip of JavaScript
- FiveJS
- SuperheroJS
- Front End Buzz
- PonyFoo
- Hacker Newsletter
- FrontEndFocus
- WebDesigner News
- WebDesigner Depot
- Ruby Weekly
- Green Ruby
- Node Weekly
- Mobile Web Weekly
- Perf Email
- GameDevJS Weekly
Hint, Panda is pretty awesome at getting a lot of content like this together.
Fullstack Bulletin might be of interest as well