For Example I really enjoy reading the "Inside design" article from the Invision Newsletter. Do you have some recommendations?
I've been liking the newsletter from Minimums a lot. It's curated by Need/Want team that has gained a lot of traction with their Peel case and Emoji masks. http://minimums.com/
The Modern Desk from Kai @ Offscreen
Really big fan of this one
Probably the best I've found recently on product is the Product Design Weekly from the folks at Atomic. They have a preview in that link so you can see what kinda things they send, but there's always something that makes me click.
maybe not what you are looking for but i signed up for the creative class email preview and it was pretty beneficial. only 7 days long but i would recommend it (and the class so far seems pretty good)
Sidebar.io, Briefi.ng, Today in Tabs
I really like the Creatively newsletter.
I've always enjoyed getting Austin Kleon's newsletter. You can tell he spends a good amount of time thinking through the stuff he sends out. It's always thoughtful and usually about the creative process.
+1 for the Invision Newsletter. I look forward to getting it every Thursday.
Not specifically design related, but I love NextDraft by Dave Pell. I read it daily. Great for keeping up with the news, learning interesting things without digging through RSS feeds and it's entertaining.
Volley.Works - its one of the most helpful communities I've found in a long time.
I really like the MyFonts monthly interviews they send out. They did an interview with Eric Spiekerman once.
http://www.vanschneider.com/ from Tobias Schneider!