Cavani, Matic, Mata, Pogba, Lingard, Grant. Likely followed by Henderson, AWB, Bailly, and Jones. I wouldn't be surprised to see Telles leave as well, Martial if there are any takers on the planet for him, and one or two of the fringe players at least (Pereira, Laird, Garner, Chong, Mengi, Tuanzebe, Pellistri). If Garner is not getting minutes here next season, given the reported Prem interest, he might be sold. Laird has just been linked with a swap move for Max Aarons (do hope Laird stays and gets a chance). Chong has a year left on his deal, Pellistri won't fancy hanging around too much at a club that doesn't know how to manage his loans given he's broken into the Uruguay squad.
I predict we'll see around 15 players leave this season and 5 arriving, 6-7 youngsters given chances.