I found a pattern for leaves & leaf chains here. http://www.fablehandmadegoods.com/Crochetpattern-leaves.html
I made a few samples to try them out with different threads & hooks.
Here's a chain I used on a card with a flower. I can see tons of possabilitiesfor these leaf chains
And here's the whole card. I had fun with this one. Used a bunch of scraps I had laying around. Love this color combo.