Could it be Drift / TiddlyWiki? https://ramirosalas.com/# https://ramirosalas.com/#: (edit: note the colon in the url, then you get "a content area with multipl

Could it be Drift / TiddlyWiki? https://ramirosalas.com/# https://ramirosalas.com/#: (edit: note the colon in the url, then you get "a content area with multiple cards on the right, dark mode, list of tags/filters on the left") If not, then I think TiddlyWiki [1] will be perfect for the usecase you mention. You can choose between a single-file version or a node.js version. The former will be a HTML+js file which is self-contained. The latter will save all your cards (called tiddlers) in separate files which can easily be versioned. Both supports markdown by plugin [2]. Since it uses HTML and js, it will continue working as long as web browsers don't make major changes - and if that happens, you will still have all your data available in either the source code or text files. A tiddler has fields such as title, text and tags. But you can add other fields such as author or source or whatever. The field values can then be accessed as {{title!!fieldname}}. This demonstrates one of the real strengths of tiddlywiki: transclusion. Transclusion, combined with filters, opens a lot of possibilities. As tiddlywiki is quite customizable (see https://dynalist.io/d/zUP-nIWu2FFoXH-oM7L7d9DM https://dynalist.io/d/zUP-nIWu2FFoXH-oM7L7d9DM), you may want to have a look at some variants for inspiration, such as RR-TW (https://rr-tw5.github.io/ https://rr-tw5.github.io/) or Stroll (https://giffmex.org/stroll/stroll.html https://giffmex.org/stroll/stroll.html) [1] https://tiddlywiki.com https://tiddlywiki.com // https://nesslabs.com/tiddlywiki-beginner-tutorial https://nesslabs.com/tiddlywiki-beginner-tutorial [2] https://tiddlywiki.com/plugins/tiddlywiki/markdown/ https://tiddlywiki.com/plugins/tiddlywiki/markdown/