I have stumbled upon a brilliant little site vintagerio.com that lets you download for a fee, vintage labels, post cards and various other cute colourful artworks from years ago, including seed packet art, my favourite.
It is worth browsing through all the pages for inspiration. How I long to be a whizz on an iMac and be able to re-create some of these designs in wedding stationary and thank you cards. I don't know of anyone who does this kind of unique design, apart from Lucky Lux in the US.
Here are some of my favourites, I haven't downloaded hence they are watermarked.