I got all the items, all those related to the races are obtained when you have used all their evolutions
The items in the lower area are obtained by completing the main story of the game
By the way, I recommend playing the battle against the queen since it is where you can get soldiers more easily and since it is one of the longest missions, it is more likely that you will get a tier 3 evolution. There is also a specific object that is only obtained when you use 2 objects at the same time it's the key and the adventurer's chest (you don't have them yet, but when you have them, use them to get the hero's sword).