In that vein, I've tried to create something vaguely trello-esque but more geared toward knowledge management rather than project management: https://www.contab

In that vein, I've tried to create something vaguely trello-esque but more geared toward knowledge management rather than project management: https://www.contabulo.com https://www.contabulo.com. Specifically, I think it's much nicer for longer articles/documents than what you would typically put in a "card" on Trello. Very much still working on it :)