Gets first <count> card titles of a Trello list (<listName>) and puts them into a string you can then use to paste them onto another board.

example.js

console.log(
    getTrelloListItemsStr('Ready for Dev', 9)
);

trello-get-list-items-str.js

/**
 * Gets first <count> card titles of a Trello list (<listName>) and
 * puts them into a string you can then use to paste them onto
 * another board.
 *
 * @param {listName}    name of the list to get the cards from
 * @param {count}       number of cards to get
 */
var getTrelloListItemsStr = function(listName, count){

    var listHeads = document.getElementsByClassName('list-header-name'),
        resultStr = '';

    for(var i = listHeads.length-1; i >= 0; i--){
        var currList = listHeads[i];
        if(currList.innerText === listName){
            
            var cardTitles = currList.parentNode.parentNode.getElementsByClassName('list-card-title');
            for(var j = 0; j < cardTitles.length && j < count; j++){
                resultStr += '- '+cardTitles[j].innerText+'\n';
            }

        }
    }

    return resultStr;
};