Object count

I create objects at runtime. How i can count how many objects i create and delete them if i have too many objects in scene.

I assume you have some sort of main script.
Increment a counter every time you create/instantiate a new object and decrease it when you delete one.

How i can find the first object, which i create in scene. All object have identical names ragdollprefab(clone).

Store them in an array as you create them.