Need help managing a lot of videos in separate folders

I'm going through some old folders that have subfolders, subfolders, and some more subfolders - and inside this mess are thousands of videos that I need to delete, organize, or move elsewhere.

Is there a tool to do this? Ideally something that creates an image sheet preview of each video and lets you look through all of those sheets easily, and can delete or access the video from the sheet.