Here's my initial thoughts
Decoy sounds very situational and only useful with dagger, in which case it becomes extremely powerful for a common
Cow is also busted for the same reason
Dandelion is a worse hiker
Norimaki sounds very interesting, good idea
Sharktooth Necklace is also a great idea, though I would change bonus cards to add chips instead of mult
Clownfish sounds very underpowered, negatives are still only 1.5% chance of appearing with the buff
Headhunter is very powerful for a common, I would change it to have to play/discard that rank in order to destroy it
Optics is very niche and entirely reliant on getting the right boss blind
Sandevistan is good, not much else to say