Sumlit
San Claudio Bravo
He doesn't have a 30m buyout clause but Arsenal might have a buy back option on him
They have a first choice refusal, not buy back clause.
It's confusing but I Arsenal has a first choice refusal at £30m and would get 50% of the additional money above those £30m, if Barca sold Cesc to some other club for more money after Arsenal had triggered that first choice refusal.