Coordinating cards, envelopes, and postage stamps

I enjoy making greeting cards.  When I saw that the US Post Office was coming out with a bicycle stamp, an idea for a coordinating card popped into my head.  After that I checked the USPS website for other postage stamps that I could coordinate with my rubber stamps.  

Below are the cards I made.  The bicycle set even has an envelope seal that matches.  Two were birthday cards and one was a thank you card I sent to my aunt & uncle who gave me a wonderful manual typewriter (Yeah!).  

I know a postcard that has coordinating front image, postage stamp, and cancellation stamp is called a maximum postcard or maxicard.  I don't know if there is a term for a greeting card / envelope version.  I have no idea how to get coordinating cancellation stamps in the USA for postcards or envelopes or if the USPS even gives an option unless it is a special event of a first issue or something.