Pokécharms

Akinator has some crazy good guesses tbh.

I trip him up sometimes but that's like throwing out the latest characters from light novels whose anime hasn't even aired yet xD

Youtuber's are also fairly popular, you probably need someone more niche.

Another trick is to throw out a character that appeared in a manga short and/or an OVA (or literally anything else) who no one at all remembers because they only appear in it for like one minute or three pages of whatever it is is if it's not a well-known minor thing despite being connected to an actually well-known thing~
*cough cough*Satsuki Asui*cough cough*

Yep, we tricked him several times, actually. Rush Melendy from the Melendy Quartet books and John Walker from the Swallows and Amazons series. Both main characters in their books, but in today's world nobody thinks about great books like them anymore. He also asked some very, very strange questions that you wouldn't expect after his previous ones.