Hi Antonia, thanks for the feature request.
Here's a couple of options.
1. Here's a link that allows you to export your message names and open rates.
https://app.ontraport.com/#!/message/export&prevAction=listAll&id=&criteria=%7B%22conditio[…]mAll%22%3A%221%22%7D&history_selection_list_performAll=true
2. If there's not a ton of pages of messages, you can cut/paste the stats by highlighting the text on the message collection page and paste it into a spreadsheet.