These cards are so cool! I love how different they all are. I think my favorite (though it’s hard to choose just one) is the Sudowoodo pokemon card! It just makes me smile looking at it.
I’m in love with your haunted house! I concur, the small size of an ATC is more manageable. I look at 4x6 cards and I’m scared of all the space to fill!
Love the Coffee, the Haunted House and the Snowy Trees. Great mug rug, wallpaper and cup shading on the Coffee Cup. Great moon, sky and architecture on the Haunted House.
I also love watercolor painting too, and working in tiny spaces. It’s the clarity and transparency of the colors that I love, though saving whites is no fun, except when you succeed. 
Your watercolor skills are very good. All of your ATCs turned out great!
These are beautiful!! It’s wonderful that the ATCs have sparked so much creativity for you, I’m looking forward to seeing what you paint next!