One common theme is the clash of cultures. Naruto's world is full of ninjas, honor, and complex politics, while minions are all about fun and chaos. So when combined in fanfiction, there's often a theme of how these two very different cultures interact. For example, how the minions' carefree attitude affects the more serious ninja in Naruto's world.
One night, a minion decided to go on an adventure outside the minion village. He walked through the dark fields. Suddenly, he saw a big, black shape in the distance. It looked like a huge monster. The minion froze in fear. As the shape got closer, he could see that it had glowing red eyes. He tried to run, but his legs felt like jelly. He managed to hide behind a big rock and waited until the shape passed by, shivering all the while.
One great 'naruto minion fanfiction' could be 'Naruto and the Minion's Adventure'. It combines the unique world of Naruto with the fun and silly elements of minions. In this story, Naruto might encounter minions in a strange new land and they end up going on a quest together, with Naruto's ninja skills and the minions' zany antics creating an interesting dynamic.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of various fanfictions, and there's a good chance you'll find some great Gru x Minion ones there. Just use the search function and type in 'Gru x Minion' and it should show you relevant stories.
In another fanfiction, Gru could be sick and the Minions take on the role of taking care of him. They try to cook for him, but of course, being Minions, they make a huge mess in the kitchen. However, their love and loyalty to Gru shine through as they do their best to nurse him back to health.
There could be Minions' daily adventures like finding a new type of fruit in the jungle. Maybe they had a race during the day and the loser was a bit sad at bedtime but his friends cheered him up.