I don't think there's a general search engine content ID system for memes. as they tend to get copied/watermarked/edited by repost pages it would be a hard thing to track. though audio wise they could be picked up? don't know if there exists an audio copyright database of memes though
as for finding the most shared and edited ones i'd look at big youtube react based channels, find their social media and see who they follow, as job-wise they have to be pretty up to date/slightly ahead of curves to get good content