As Cocktail basically makes Potion a Gold+ if you connect two of them, it seems a bit unrewarding to me. I'm not as sure here, as the first comparison i can think of is Treasure Map, which only works once and is terminal, but gives a much more effectful reward. Horse Trader also comes to mind, and again has a few disadvantages over Potion (discarding, terminal), but also is much more flexible and has a Reaction.
Graduate seems cool and is easy to get. It's probably the one that works best as a Potion event because it doesn't do too many different things. Unicorn also is pretty easy - but isn't it a bit weak compared to Expedition, even with the +Buy?
I also like the idea behind Transfigure, although there i actually feel it would work better as an Action card. Maybe it's a bit too strong to be able to buy any $5 for just $4 by making the first one (non-terminally) dead. Consider Feast as a comparison, although of course even Feast has an advantage being able to gain VP cards.
While i think that Magic Amulet and Ghost Hunt are cool, i think they do a bit more complex than i would expect from an Event. Ritual is kind of on the edge here for me.
The main comparison for Cocktail is Fool's Gold, which is very powerful. Maybe +$7 is better and there's room for more interesting effects.
Unicorn was my attempt at turning Stables into an Event, but $1P seemed too cheap given all the ways you can make $1.
Transfigure is better than Feast (it's basically Feast, and the card you gained costs $1 less for the rest of the game), but Feast is really weak to begin with. Graduate is also a Feast variant (you can trash the potion to gain a $5).
For Magic Amulet I was thinking of the "you get 2, everyone else gets one" effect, realised it would need to be non terminal (since another player getting an effect is equivalent to them playing a cantrip with that effect), then thought it could be a Treasure, then I remembered this thread.
Ghost Hunt sprawled in complexity as I was typing it: "What if you draw a good card? Top deck option. Does it get too strong with stacking? Once per turn. Does it get provinces too easily? Trash the potion".
