Well, a lot of One Punch Man fanfictions about heroes seeing Saitama are really interesting. Some focus on their initial shock at his power. For example, Genos is always in awe of Saitama's strength in the original work, and in fanfictions, this can be explored even deeper, like how he tries to understand the source of that power.
It ends at a specific chapter, but I can't recall exactly off the top of my head. You might want to check online manga forums or dedicated One Punch Man fan sites for the precise chapter.
You can find 'One Punch Man' fanfictions on websites like FanFiction.net. It has a large collection of fan - created stories related to 'One Punch Man'. There are different categories and ratings, so you can easily filter and find the ones that suit your taste.
One Punch Superman was now finished. Although the story was very exciting, due to the limitations of the story rhythm and battle scenes in the manga, the development of the story did not reach the height of animation. Therefore, some people thought that it ended in a hurry.
There was no official news on whether there would be a second season. However, the original manga of One Punch Superman had received a lot of attention and love from readers in the past few years, so if the animated version could be successful enough, it was likely that there would be a sequel.