I have been into "collection drawing" lately. I have been drawing buildings of LA, all of my restaurant receipts, rabbits I find on Google image search, coins of the world. Strange I know, but it is a lot of fun.
When I came across the Zentangle drawing below that I did many months ago, I realized I had another "collection drawing." After I scanned it, I took into Adobe Illustrator and practiced using the color guide and edit feature. The options are endless.