Griezmann to Utd
Neymar to PSG/City
Dybala to Barca
Kane to Madrid
These are the only possibilities that I can really think of right now. I don't think Muller would move or necessarily fetch a WR price, don't think Verratti would either simply because of his position and style, Bale to Utd is potentially a possibility but I think he's happy in Madrid nowadays and has the chance to be their new poster boy when Ronaldo moves on.
The top two I think could happen as soon as next summer, I think Dybala would need a couple of years to fully establish himself as an elite talent even if he has a great season this year, whilst Kane I think to get that kind of move would have to happen after the 2018 World Cup and he'd had to have a great tournament to establish himself as the new poster boy of English football.