I had a play with my tag and envelope templates last night to see what I could do with them aside from straight tags... I made some folded tags/cards by placing the colluzzle on a folded sheet of cardstock...
And I made three different versions of a library pocket - the first one is a mini-envelope with the flap trimmed off and a small rectangular tag... the second is a mini-envelope with the flap left unfolded and a regular tag. And the third is the mini-envelope flipped to have two 'long' ends and a 'stretched' tag to go with it. Which of the envelopes do you think looks best?