From our loanees, we can cash in on Lingard, Pereira, Chong, Dalot. Let Mata and Jones leave for free. And from our first team we could sell Dan James, Matic and Tuanzebe, if we bring replacements RW, DM and CB. Brandon can go out on loan and we can bring a new RB as well.
De Gea and Martial will be impossible to sell. Huge wages and still a couple years left on their contracts. We can try to loan De Gea, similarly to what we've done with Alexis, paying part of the wages.
Donny and Telles won't leave. They can improve next season.