This is a basic Object Pool for Unity.
Drag in 1 of each object you want to be in the pool. Then call GetPooledObject when you need one.
if it doesn't have one availible, it will spawn 1 new one and place it in the pool.
This will change your spawn rate each time, however i have no found it to be an issue.
Later i will upload some variants for different needs, such as theme, or weighting based on odds.