Honestly, the Akatsuki robe memes are maybe the funniest corner of the whole fandom to me. That stupid red cloud pattern is instantly recognizable, so people just slap it on anything vaguely ominous or dramatic. The classic is that 'Akatsuki having a group meeting' meme template where they're all just standing around looking bored or arguing about petty stuff, which feels weirdly accurate for a group of S-rank criminals. My favorite iteration was the one about Pain trying to explain his elaborate 'cycle of hatred' plan and the other members are just checking their phones or asking if the meeting is almost over because they have laundry to do.
Another huge one is the specific pairing of Hidan and Kakuzu. Their 'immortal duo' dynamic got turned into this eternal bickering married couple bit. You'll see endless comics of Hidan being chaotic and spending all their mission money on junk food, while Kakuzu just sighs and tallies up the damages in his ledger. It's such a weirdly relatable domestic take on two guys who are literally murderers for hire. The fandom really latched onto that grumpy/sunshine dynamic, even if sunshine in this case is a blood-crazed cultist.