Ability to make a trello card from a note in agenda and have the two linked - so you can see the link to the card in agenda but see the note from agenda on the trello card.
Note that you create an agenda link using the cog button on each note. You could paste that in Trello to open Agenda later.
I’m guessing the same would work the other way. Get a Trello link, and put that in Agenda.