How many bound items can you have?
By "bound" I am referring to features which state something like "you receive [some item] as a bonded object".
For example, the wizard’s bonded item option, the magus’s blackblade archetype which is a bound weapon, or ioun bound arcane discovery.
As far as I can find, there is no rules text about bound items, just that you only get one from each class feature that gives you one, such as the features described in the question. There are no other rules about bound objects aside from what is explicitly described in those class features.
There is no upper limit.
Some specific items limit you to an amount of its type (like "only 1 black blade"), but you can have as many objects as you want.
A wizard multiclassed with arcane sorcerer can select 'bonded object' on both, getting 2 objects. they need to be separate ones (not the same amulet), and they ant cross class (the wizards ring doesn't give you an extra sorcerer spell)
