In his Monadology Leibniz writes:
each portion of matter can be conceived as like a garden full of plants, or like a pond full of fish. But each branch of a plant, each organ of an animal, each drop of its bodily fluids is also a similar garden or a similar pond
This can be described analogically, I think, as a fractal - where each part also describes the whole. It can also be described analogically by the set theory multiverse where every set theory contains the entire multiverse itself. Of course both fractals and set theory multiverses are contemporary developments in mathematical thought.
But there is also perhaps a more puzzling antecedent. Indras Net is a metaphor developed by the Mahayana school of Buddhism in 3rd century CE India, and in the 6th century CE Chinese Huayan school.
Francis Harold Cook in his book Hua-Yen Buddhism: The Jewel Net of Indra describes this metaphor thus:
Far away in the heavenly abode of the great god Indra, there is a wonderful net which has been hung by some cunning artificer in such a manner that it stretches out infinitely in all directions. In accordance with the extravagant tastes of deities, the artificer has hung a single glittering jewel in each "eye" of the net, and since the net itself is infinite in dimension, the jewels are infinite in number. There hang the jewels, glittering "like" stars in the first magnitude, a wonderful sight to behold. If we now arbitrarily select one of these jewels for inspection and look closely at it, we will discover that in its polished surface there are reflected all the other jewels in the net, infinite in number. Not only that, but each of the jewels reflected in this one jewel is also reflecting all the other jewels, so that there is an infinite reflecting process occurring
Leibniz was notoriously well read - did his reading stretch to Buddhist Philosophy? Of course establishing priority claims is tricky and perhaps futile; it may simply be a case of similar ideas arising independently, and the interest lies in how these similar ideas have imbibed the quality of their own philosophical climate as well as how and in what quality they differ manifestly and subtlely from each other.