Here are the favorites of mine that are still around and active.
Erica Sadun (Twitter)
I’ve known about Erica’s work since the 2013 Edge Cases episode “Rectangles on a String”. (I even know how to pronounce her last name, even if she does pronounce tuple wrong.) Her blog updates several times a week, often about some detail of Swift development. She’s written a bunch of books, mostly focused on developers, and one book on Swift.
Becky Hansmeyer (Twitter)
From her own description, her blog is “my own little place to comment on Apple & general technology news, as well as what it’s like to be a novice developer with no prior programming experience.” Her tag line is “100% grass-fed Swift”.
And finally, a great blogger who’s been very active recently who’s not on the list: