Wekan: An open-source Trello-like kanban
If you want to do Kanban right, double down on making it possible to design actual Kanban workflows. Pretty ticket UI with checklists and GIFs must be secondary to this goal.Things that most actual Kanban flows have that no one has built into a decent product[0]:    - Nested columns in lanes
    - Rows for class-of-service
    - WIP limits (per lane, per column, and per class-of-service)
    - Sub-boards for meta issues

The actual content of each work item is the least important part of Kanban; it could be a hyperlink for all I care. Kanban is about managing the flow, not managing the work.[0] Please prove me wrong if there is such a product out there!