One possible plot could be that Ash discovers a special Shinx that has a rare ability. This leads him on a quest to find out more about this ability and how to help Shinx develop it further. Along the way, he might encounter trainers who are also interested in Shinx's unique ability and try to steal it or challenge Ash for it.
A plot could revolve around Ash and Shinx entering a tournament that is dominated by Fire - type Pokemon. Since Shinx is Electric - type, it has an advantage over them. But Ash and Shinx would have to face tough opponents and overcome various obstacles to win the tournament. This could include training hard, making new friends who help them, and dealing with trainers who use underhanded tactics.
A fanfic centered around Ash and a Shinx starter could be really exciting. Since Shinx evolves into Luxio and then Luxray, there could be a great character arc for this Pokemon as it grows stronger with Ash. The story might also explore how Ash trains Shinx differently from his other Pokemon, and how their bond develops over time. It could involve Ash traveling to new regions or facing off against new types of trainers because of his choice of Shinx.
Maybe the fanfic could revolve around Meloetta having a special mission. Ash gets involved when he meets Meloetta. For instance, Meloetta needs to collect certain musical notes scattered across different regions to unlock its full potential. Ash helps it on this quest, and they face challenges like harsh weather, difficult terrains, and other Pokémon that are protective of the areas where the notes are hidden.
The plot can be quite exciting. It might involve Ash's adventures with Shinx, facing various challenges and making new friends.
One possible plot is that Treecko gets separated from its trainer early on. It then has to find its way back, facing many dangerous Pokemon on the way. During this journey, it learns new skills and becomes more independent.
One common plot is that Ash discovers a hidden egg of a legendary starter Pokémon. He then has to protect it from poachers or other trainers who want to use its power for evil. Another plot is when Ash is chosen by a legendary starter Pokémon to be its partner to save the Pokémon world from a great threat.
I'm not sure specifically as 'ash goomy starter fanfic' could be about a lot of things. It might be a fan - created story where 'Ash' is a character and 'Goomy' is some sort of creature or entity, perhaps a starter in a game or a unique being in a fictional world. But without more context, it's hard to say exactly.
The plot could start with Ash getting Riolu as his starter Pokémon instead of Pikachu. Riolu might be a bit of a troublemaker at first, not fully understanding Ash's commands. But as they journey together, they start to understand each other better.
Maybe in the fanfiction, Trapinch is a rare and special Trapinch that has some kind of ancient power. Ash discovers this and has to protect Trapinch from villains who want to use its power for evil. Along the way, Ash and Trapinch form a really strong bond as they face these threats together.
Well, in this fanfiction, perhaps Ash stumbles upon a Mudkip that was abandoned by its trainer. Feeling sorry for it, Ash takes it as his starter. They start their journey together, and the Mudkip has an unusual ability to communicate with water - type Pokémon. This leads to some interesting adventures as they encounter water - based mysteries and help other Pokémon in distress. They also have to prove themselves to other trainers who doubt a Mudkip as a starter.
One possible plot is that Latias is injured and Ash finds it. He nurses it back to health, and during this process, they form a bond. Latias then decides to join Ash's team. Another plot could be that there is a tournament where the prize is a special item that can attract Latias. Ash enters the tournament, wins, and uses the item to catch Latias.