There is a genre of music that my old roommate was into which titled all of their songs and albums in obscure Unicode characters with no known pronunciation. Songs in this genre may not be perfect antimemes, but I think their resistance to reference is an antimemetic property.

Also, chromosomes are nucleotide-encoded memes, and linear ones use teleomeres to impose limits on the number of replications they support, so that's another imperfect antimeme.

I know of no antimemes whose antiemetic nature comes from their ability to interfere with the human mind, but then again, I wouldn't know about them if they existed, which is more or less the book's point.