There is no quick answer but here goes. I joined imgflip years ago, even back then it was obvious many of the regulars used alts to get past 24 hr bans and to agree with themselves when they were losing arguments. That has never changed. The main trolls all use alts, most conservatives do not. I don't and never have. I also do not follow people I do not respect. I have no idea which trolls make and post memes, I just don't care. The trolls that are just here to start drama follow a pattern, they attack the messenger, not the meme, use insults, cartoons and circular arguments to distract and always abuse the TOS policy most of the time without penalty. Which I think shows the mods themselves create drama using alts just to use timeouts to punish conservatives.
Since I have been on imgflip I have been accused of stolen valor (I really am a vet), being a cop in Fla, and Alabama (never been in law enforcement, no clue where that came from, being a Chinese, Russian and other bot, being a blacksmith (that was almost true, worked with one years ago) being a 70+ year old man (pretty sure they meant my Uncle but he is not that old, so again I am not really sure where that came from) and a dozen other things. The trolls all seem to fixate and stalk conservatives. The conservatives do not do any of that.
My point is the pattern is as old as imgflip, personal attacks threats to call customers and wreak businesses, insulting users and their families only go in one direction. Conservatives do not do any of that, they hold themselves to a higher standard. People with friends and family in the real world do not need to cause drama to make themselves feel powerful, or live to insult strangers online.
Here is how you find the alts. Find a thread with lots of drama and a high number of responses. Screen shot everything, go back and replace all the names, the mix of initials and letters can confuse AI. Once the names are changed and for example you changed OGMAGA to userone and every other person posting was given the same thing user and a number, userone through userthirty (as an example). It takes time but find and replace makes it go a little faster, the point it to make it easy for whichever AI program you use to follow the thread and to ID the users. Ask the AI to compare the sentence structure, punctuation and all the other metrics you want to know and in less than a minute it usually shows which users are the same person.