Trello Filters

gform_trello_card

This filter can be used to change the card properties before sending the data to Trello.

gform_trello_field_value

https://docs.gravityforms.com/gform_slug_field_value/.

Trello Feed Meta

The Feed Object meta for the Trello add-on is an associative array containing the properties which determine how the add-on should process the form submission.