The search tool will work fine for this. Use the find routine (CTRL+F) to open the find dialog

With the wildcards box checked and the highlight all found entries box checked . . .

Search for . . . .
[a-zA-Z0-9\-_.]{1,}\@[a-zA-Z0-9\-_.]{1,}

The e-mail addresses will be highlighted.

Close the find dialog. Then copy to the clipboard.

Open a new document and paste.