A crossover with Minecraft would also be cool. The goose could waddle into the blocky world, disrupt the building projects of the players. It might steal their resources like diamonds or iron, and peck at the creepers just for fun.
One interesting plot could be the goose forming an unlikely friendship with another animal in the village. For example, the goose and the cat team up to prank the villagers in a more elaborate way than the goose could do alone.
First, decide which universe you want to crossover with. Then, think about how the goose's personality and actions would fit into that new world. For example, if it's a crossover with a fantasy world, the goose might be seen as a strange magical creature.
The 'untitled goose game' is about a naughty goose causing mischief in a village. The goose goes around stealing items, honking at villagers, and generally disrupting the peaceful village life.
Maybe there's a goose that discovers a hidden shortcut on the game board. This goose then has to decide whether to share it with the other geese or keep it for an advantage in the game. The story could follow the moral dilemma and the chaos it causes among the geese and other players.
The goose itself is obviously a very popular character as the main troublemaker. People often write about its mischievous antics in great detail.
A simple plot could be the goose getting lost in a new area of the village that has never been explored before. It then has to find its way back while causing chaos along the way.
The main character is the goose, of course. And there are various villagers like the gardener, the boy, the shopkeeper, etc. who interact with the goose.
In 'Game of Thrones Crossover Fanfiction', a cool concept would be crossing it with 'Alice in Wonderland'. Alice could wander into Westeros and disrupt the power balance with her strange and magical ways. Another idea is to cross it with 'The Hunger Games'. Have the districts be like the different regions of Westeros and the Capitol be King's Landing. And a crossover with 'Supernatural' where the Winchester brothers hunt down the supernatural threats in Westeros.
Well, for a 'a game of thrones crossover fanfiction', a crossover with 'Star Wars' would be cool. Picture the Nights Watch using lightsabers to fight the White Walkers. Or a crossover with 'The Matrix'. What if characters from Game of Thrones were trapped in the Matrix? Also, a crossover with 'Sherlock Holmes'. The detective skills of Sherlock could be used to solve the mysteries in Westeros.
The village dog could be a main character too. It could be constantly chasing the goose or getting tricked by the goose into chasing its own tail. It might also have a soft side and end up befriending the goose in an unexpected turn of events.