I tried filling shapes with watercolour paint one evening while watching tv, which didn’t turn out quite as I imagined because the card sucked in the paint more than proper watercolour paper does. I may revisit this idea, though not replicate it exactly, on better paper.
Then in the next sit down session I got the courage up to try some stamps, growing more confident and creative as I went. Some I coloured with pencils, others I used coloured stamp inks.
The green one was tweaked in a later session.
The one with the little kiss stamp will have a “Thank you” or “Congratulations” stamped on the front depending on the purpose I use it for.