Yes Trello :-)
I never noticed there's a markdown ability in that app. I've only ever used Trello a couple of times, and as much as I'm a fan of kanban and scrum (which, if you've never heard of it, is very much similar to kanban), I never caught on to how useful it is.
I... MIGHT give it a go once I'm convinced GitHub doesn't work to my liking. I'm more active on that platform, and GitHub uses the exact same markdown language as Steem, so copying over the content on its whole from GitHub into Steem should be seamless, both technically and formatting-wise.

Thanks for your comment!