Id like to drop some ideas I had for some mental and physical transformation:

Physical Transformation:

Gynecomastia: Kinda like the Feminitiy transformation but more manly, whoever recieves this card will receive man boobs the size of melons, this can also be combined with Lactation to create your very own milk cow. ;)

Nullify: Again, very similar to Reduction, but I like to think its WAY more extreme, instead of just shrinking the cock, it nullifies the bluge entirely, leaving only a small bump of skin near the crotch.

Dehydration: Opposite of Fluidity, makes it so the targets balls shrink to the size of seeds, and they can only create little burps of cum.

Urination: Makes the subject completly and utterly lose control of their bladder. Making it difficult for them, can potentially be combined with other cards for different effects ;)

Mental Transformations:

Obedience: Similar to Inferiority, but much more extreme. Whenever someone is given Obedience, they are automatically compelled to do whatever the other players say, no matter what it is. They can literally be told to strip naked and talk about their tiny dick for a solid hour and theyd do it.

Devolution: A more extreme form of Fatuity, turns the target into a walking caveman that barely knows how to speak or play cards. They scratch their forehead, and only know the primal urge to mate.

Additonal Note:

Second level Transformations. For example with the Atomity transformation, make it so you can shrink someone down to the size of a barbie doll.  And the opposite way should work too! With the Stature transformation, make it so that person can become a giant that can only barely fit in the apartment. 

Let me know your thoughts!