Bonus points for essential oils and botanicals that are actually toxic to cats and sometimes also dogs 🙄 Lavender. Tea tree oil. Peppermint. Eucalyptus. Grapefruit oil. Orange oil (basically citrus oils in general). Patchouli, which contains phenols. ALOE VERA. ST JOHN'S WORT.

Edit: The Aloveen the vet gave me also contains Aloe vera. side eye

To be fair they're mostly for dogs but there isn't much out there I'd risk using on a cat and some of those ingredients are toxic to dogs as well.

I found one unscented option - Dermacare Natural Shampoo - and was about to buy it until I googled Glydant (DMDM hydantoin). It's an antimicrobial preservative that releases formaldehyde and was the subject of a lawsuit against Tresemme. Suspected in multiple cases of allergic reactions/dermatitis and hair loss. It's not the only formaldehyde releasing preservative but a commonly used one in makeup, shampoo, lube etc.

Yeah nah get fucked. I'm not risking it. I don't feel like dragging my cat to emergency for an asthma attack, allergic reaction, or poisoning because she licked some shonky product off her fur. Hypoallergenic dish soap or pure unscented bar soap it is.