Using the sword on the grindstone 10,000 times without buying the "Time is Money" DLC will display a message from Ben Kane, founder of Going Loud Studios, telling the player that using the grindstone wasn't worth the time.
Contributed by ThisGuyInTheSuit
In the add-on "Live Freemium or Die", before you fight the final boss he says, "You think microtransactions are your ally. But you merely adopted the freemium. I was born in it. Molded by it." This is a reference to the character 'Bane' in the movie The Dark Knight Rises.
Contributed by PixelatedGam3r
On one of the gravestones in "Live Freemium or Die" reads:

"Here Lies:

Villager Jon

Killed by the Creatures. Real Talk? He Wasn't Paying Attention."

This is a reference to the online show "Game Grumps" and its former host Jon Jafari "JonTron".
Contributed by KnowledgeBase