These are 2 threads where you will find a lot of interesting blogs: https://news.ycombinator.com/item?id=4000394 and https://news.ycombinator.com/item?id=7083921.

In my Feedly I follow Seth Godin's blog, Priceonomics and The Changelog.

http://www.joelonsoftware.com/

I don't think there have been many good blog posts for years (it's just promotional stuff now). But on that page, check out the middle column on the right that recaps the best posts.

rc3.org