Let me just dive straight in: you're asking about the Marauders on Wattpad, and the sheer volume is overwhelming. Sorting by trending is a decent first step, but it often rewards updates over quality. A title that keeps showing up is 'All The Young Dudes' by MsKingBean89—yes, it's massive and migrated from AO3, but on Wattpad it has a different kind of community feel with loads of fanart in the comments. That's a whole experience in itself. The reading lists curated by users like 'marauderslibrary' are more useful than the platform's own algorithms sometimes.
I'm less convinced by some of the super-popular, trope-heavy ones that feel like they're following a checklist. 'The Last Enemy' series (though I think it started elsewhere) has chapters floating around, and its focus on the first war hits differently. Honestly, the hidden gems are often the incomplete, character-study ones that get buried. I spent last weekend going down a rabbit hole for a fic called 'The Third Floor Corridor' that's just James and Sirius being idiots in their early years—it's silly and sweet and only has a few hundred reads, which feels criminal.