I was going to add Arts & Letters Daily to my other comment as another mention. A&L Daily is an interesting feed but I have to admit I don't read it as often as something like HN and haven't kept track of it in awhile. It doesn't have the "current news" character of something like HN and is a bit hit or miss in terms material feeling compelling enough to read thoroughly, at least for me personally.

At the same time, A&L Daily curates a certain type of content that I haven't seen targeted anywhere else in a feed/aggregation. There's a certain amount of overlap with HN, but it's kind of complementary. I wish there was something like A&L Daily that was updated more often, with more material, but maybe it's just not out there.