Compared to more modern tools Jira is actually not very flexible.
For me the most flexible and useful tools are Kanbanize[0] and Kaiten[1].
Both companies are engaged in furthering the Kanban method which also means they care about having a lot of features for displaying cards, limiting work in progress, defining workflows and have solutions for working together on bigger workflows with several teams.
I use both professionally.
A lot of other solutions have assumptions built in which really limit flexibility. One example in Jira is the coupling between workflow status and columns on boards.
For me the most flexible and useful tools are Kanbanize[0] and Kaiten[1].
Both companies are engaged in furthering the Kanban method which also means they care about having a lot of features for displaying cards, limiting work in progress, defining workflows and have solutions for working together on bigger workflows with several teams.
I use both professionally.
A lot of other solutions have assumptions built in which really limit flexibility. One example in Jira is the coupling between workflow status and columns on boards.
[0] https://kanbanize.com
[1] https://kaiten.io