Gentleman Stationer looks like it hasn't been mentioned yet. The blog features a regular Sunday links post (similar to what Pen Addict does) that points to other sites as well.

It's not a blog, but you could try the Pendemic Discord: https://discord.gg/pendemic

I'm really hoping this community builds up, though, as I'm not a huge fan of Discord as a discussion board. I really need to post my collection and start contributing!

@coys25 I'll plug my own one :) and then a few others I know or subscribe to. Many blogs also regularly post roundups full of links to other blogs.

https://inksync.goldgust.net/
http://inksharks.blogspot.com/?m=1
https://www.afleetingripple.com/
https://www.mnmlscholar.com/
https://lefthookpens.com/
https://extrafinewriting.substack.com/
https://fromthepencup.wordpress.com/
https://www.handoverthatpen.com/
https://weirdoforestpens.wordpress.com/
https://stationery.pizza/