I send out a lot of birthday postcards. It used to be a simple, inexpensive way to send a large quantity of birthday greetings. It's still simple but not so inexpensive. Here's the September version; it uses all Studio 490 stamps and Ranger archival inks.
Prairie Art Stamps who in turn learned it at Stampaway from ImpressionObsession*. I've used a similar method in the past but not so much with a lot of background stamps.
All About Art (dots, sentiment): Crimson, Jet Black archival ink
Dimensional Rose Art (numbers background): Monarch archival ink
Be Inspired...Make Art (plaid background) Chrome archival ink
Nature's Art (leaf stems): Olive archival ink
Sakura Micron markers (squiggly border line)
*I couldn't find the tutorial but did find the 'cover-a-card' samples to be a big help in determining stamps and colors to use in a pleasing manner. Their site offers quite a few samples of this technique; essentially you're making your own background papers. Thank you, Judy and Pam, for sharing. Sure wish I could have taken the class you offered on this technique. IO has lots of really cool background stamps and I LOVE their mega mount stamp tool.