I think in quarter final form these will be France,Germany,Portugal,Iceland,Belgium,Poland,Wales and Italy.This is my prediction to see these team in next round.I see Italy dangerous and it will make surprising move after defeating Spain.Germany is much better than Slovakia by all aspects and means of play.
You think that Iceland win versus England? Okay they created the surprise in the group F, but even if England did not do a good entry in this Euro I think they will win versus Iceland 
England will probably the last team that someone will consider to bet their money on, so far they are the worst among all those top country out there except for portugal. Premier league is the best league in the world and yet their player mostly play in there but still they are having trouble in most of their game
But England is also a good team though, i'm sure England can win versus Iceland. Belgium is good too, i think they have a big chance to win on Euro 2016.