I like Zotero, which is developed for academic reference management, so it can work with longform articles, blog posts, as well. It has zero recommendation features and very limited group support, which I see as a feature.
Zotero is great for keeping an inventory of your books. Super easy to add books just by entering the ISBN and sometimes tweaking the fetched entry a little.
I always export the books we have to a spreadsheet file for reference on my smartphone when we're going to a second-hand book fair.
