Fan-made One Punch manga can range from amazing to mediocre. It often depends on the artist's style and how well they understand the original characters and themes. Some manage to add new perspectives, while others might struggle to replicate the charm of the official work.
You can try looking on some popular manga-sharing websites or forums. Some specific ones include MangaFox or MangaReader. But be careful as not all fan-made manga might be legal or of good quality.
Manga are usually made by a team effort. A mangaka comes up with the story and does the initial sketches. Then, assistants help with inking, coloring, and adding backgrounds.
Manga is usually created by a mangaka who comes up with the story and does the illustrations. They start with a concept, draft the characters and plot, and then do detailed sketches and inking.
The Made in Abyss manga is on hiatus for now. Maybe the author needs time to flesh out the story or there could be other behind-the-scenes factors affecting the schedule.