First off, I'd like to thank tim17 for this excellent puzzle. Here's my first take.
EDIT: majiponi found an exploit that leads to unbounded play thus disqualifying this kingdom.
Sorry, but I've noticed that your Kingdom goes infinite even without Ferry.
Expand Alchemist to Possession
Stonemason Possession to Golem and Gold
Stonemason Golem to 2 Alchemists
Expand Gold to Province
Stonemason Province to 2 Expands
Removing Alchemist, no infinity, but no interest either.
Kingdom: Stonemason, Village, Scrying Pool, Alchemist, Golem, Possession, Expand, Scheme, Fortress
Events: Seaway, Training, Lost Arts, Donate, Obelisk on Stonemason
Setup: Seaway, Training, and Lost Arts on Stonemason (so it gets +1 action, +1 coin, and +1 buy)
Victory points are simply generated by Obelisk.
Starting deck:
9 Scrying Pools
1 Scheme
1 Fortress
N Expands
N Stonemasons
At start of turn
play Scrying Pool, draw entire deck
play a Stonemason on the Fortress, gaining 2 Stonemasons
play Scheme to draw one Stonemason (and to allow us to topdeck a Scrying Pool for next turn)
Start of iteration
play all Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons
play a Stonemason on Fortress, gain 2 Villages
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 2 Villages
play a Stonemason on Fortress, gain 2 Stonemasons
play 2 Villages, draw the two stonemasons
play Expand on a Scrying Pool, gain a Golem
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 1 Golem
play Expand on Golem, gain a Possession
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 1 Possession
play Stonemason on Possession, gain two Golems
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 2 Golems
play Stonemason on Golem, gain two Alchemists
play Stonemason on Golem, gain two Alchemists
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 4 Alchemists
play 4 Stonemasons on Alchemists, gain 8 Scrying Pools
play remaining Stonemasons on Fortress, gaining 2 Stonemasons each time
play a Scrying Pool, drawing a lot of Stonemasons and 8 Scrying Pools
End of iteration. This state matches the start of iteration state except we have about 128 times as many Stonemasons and 2 less Expands.
It may seem like an endless loop, but eventually we run out of Expands. Since neither Expands nor potion cards can be gained during a turn, the turn must eventually end. When the Expands run out, we keep performing the iterations just gaining and drawing Stonemasons until we are out of Scrying Pools and the action phase ends.
Buy phase
buy all of the Expands we can for next turn
topdeck a Scrying Pool (from playing Scheme)
Two Expands gives us 7 Scrying Pools, so if we start with N Expands, we do O(3.5*N) Scrying Pool passes that double the number of Stonemasons each time. That means we played O(N*2^(3.5*N)) Stonemasons for 1 buy each and 1 coin each. We can therefore buy O(N/7*2^(3.5*N)) Expands for the next turn. Our Stonemasons have increased by the same order. Therefore our growth rate is O(2^(3.5*N)) = O(11.31^N).