Trello – nyway to convert some cards to a checklist in Trello

There is no feature to do this in Trello. However, since you can create multiple checklist items in one go by pasting multiple lines into the add checklist item field, all you really need is a list of card names to copy from.

If you don't mind fiddling a bit, you can export your whole board to a JSON file and then print a list of all card names fairly easily like this:

perl -MJSON -l -0 -e 'print $_->{name} for (@{decode_json(<STDIN>)->{cards}})' < board.json

This assumes that the cards you want to convert are basically one-liners as it ignores any description, checklists, etc. in them

Another option would be to export the cards to a CSV file but that requires the paid "Business Class" license.