first things first… please refrain from asking questions about torrenting / file sharing etc. – this goes against our “keep it tidy” rules in this forum: https://forums.plex.tv/guidelines#heading---tidy
As for files not showing… this is certainly not about the file type. Plex has no restrictions preventing AVI files to show.
Your issue is most likely related to poor file naming. Please make sure you follow the Plex naming conventions – otherwise movies might be confused with other content already in your library. https://support.plex.tv/articles/categories/media-preparation/