1. Winged creatures --especially FAIRIES/FEY and including fluttery, whimsically-drawn insects and animals such as butterflies, dragonflies, flying horses, probably dragons, too, while we're at it. I don't have a problem with serious, zoologically-correct renderings of insects and animals (such as in the Celtic Druid Oracle), but those are few and far between in tarot and oracles.
2. "Prettiness" --a far cry from beauty. The best example I can think of off the top of my head is Crystal Visions Tarot. Ditto the gross offender from the 90s known as Tarot of a Moon Garden. A yawning, paralyzing boredom grips me when I see the streams of flowing hair on maidens surrounded by butterflies and unicorns against a frosted lavender twilight.
3. RWS-Heavy decks for self-readings -- same "yawning, paralyzing boredom" from above. In a newly-produced deck, I believe this to be unacceptable and will only consider the deck if I think it would be good to read for a certain niche of querent. My eyes glaze over as I flip through the usual suspects dolled up in their (often flimsy) respective themes: the Wands gentlemen staring out at their horizons; the beggars outside the house of worship; the two kids exchanging flowers; the indelible pierced heart...
4. Lo Scarabeo's Multi-lingual titles
5. Images that are too small for the intricacy of the artwork . Small images are fine for Tarot of the Trees or the African Tarot, but for Sweet Twilight, Shadowscapes, Paulina--no, no, and no.
6. Digital/CGI art that tries to look painted/drawn as opposed to blatantly collaged -- you knew it was coming, didn't you?
But here's something you should know about me. I never, ever say "never" and, unlike what our culture teaches us, I believe open-mindedness is something we all have to work towards, day in and day out. It is not a natural state of being for most people.
To that end, I recently purchased Legacy of the Divine, several years after inaugurating the Gilded as the first and only tarot deck I've ever sold or traded away. (And not only did I buy Nathalie Hertz's Faerie Tarot and force myself to use it this spring, but I am still going to give it another go at some point in the near future, winged creatures and prettiness and all.)
Here's to teaching ourselves how to turn "absolutely cannot stand" into "don't much care for but can live with."