x <- c("Anna & x, Anna & x", #
       "Alb, Berta 222, Alb", 
       "Al Pacino", 
       "Abb cd xy, Abb cd xy, C123, C123, B")

library(stringr)
str_extract_all(x, "([^\\s,](?:[^,]*[^\\s,])?)(?!.*\\1)")