I had a bunch of todos in the Things app that I wanted to move to my notes. Manually copying them from the app didn't grab the notes in the todo, which was quite a hassle. So, I ended up writing this quick AppleScript to export all todos from a specific list in the Things app, including the notes.
tell application "Things3" set inboxToDos to to dos of list "Inbox" repeat with toDo in inboxToDos set todoName to name of toDo set taskNotes to notes of toDo log (todoName & " -> " & taskNotes) end repeat end tell
Update: Turns out Things app provides a way to "Share" each list by right clicking the list -> Share > Copy as text.