The universe is split up into many island-universes, as described in the Yoga Vashishtha 6.2.60
I saw countless creations though they did not know of one another’s existence. Some were coming into being, others were perishing, all of them had different shielding atmospheres (from five to thirty-six atmospheres). There were different elements in each, they were inhabited by different types of beings in different stages of evolution.. [In] some there was apparent natural order in others there was utter disorder, in some there was no light and hence no time-sense.
I imagine this is talking about various planets in different stages of evolution.
Are there similar accounts in other Hindu scriptures?