My guess is:

This one allows you to change into any class you want only once.

This one allows you to switch into any class you want unlimited number of times for the next 180 days

This one is probably permanent

While this enables you to switch to Bard for example for the next 180 days (you have same ones for all other classes)

And this allows you to switch to Bard for example but only once (you have same item for all other classes)
Other items are fragments, i may be wrong, i am just guessing.
let me fix a bit:

- This one use for start quest, where you just need to go to goblin in bank and you can take item for change class. you will get this:

- this one its what you get from this quest. (this item for change class to bard). You can select, what class you want to get. Consumed when used! 180 days timer.

- This item also give you a quest for get class change item, but now you will get this:

- this item give you right to change your class for ather class (depends what class item you have). When you use it 1st time, you will get 1 more item what give you right to change your new class back to your start class. Not consumed when used. Cooldown 10m. 180 days timer.

- This 1 just give you right for change your class for any ather classes. Not consumed when used. Cooldown 10m. 180 days timer.
From box you can get:

- if you get x200 you can make this -

- also can drop from drop, but its rare drop.

- if you get x300 you can make thus -

- also can drop, but its realy rare. You can change this item to this -

if you get 5 of them, you can make this -

.