Attributing the existence of things to a creator is a lazy intellectual exercise. But in past ages, as my previous post drawing attention to a Cambridge University blog post indicated, some humans in the past have been prepared to try to think in a different direction. For centuries, western thought was controlled by the church, and thinking outside the strictly controlled religious box could get you into trouble. But outside of Europe and its later developments, some were free to think of a universe without divinities.
This is how Guo Xiang (born 252 CE-died 312 CE) devoted thought to the existence of things and in his Zhuangzi (which, along with the Tao Te Ching forms the basis if Daoist thought) argued that 'things' are self-transformed,
"If we insist on the conditions under which things develop and search for the causes thereof, such search and insistence will never end, until we come to something that is unconditioned, and then the principles of self-transformation will become clear ... there are people who say the shade is conditioned by the shadow, the shadow by the body, and the body by the creator. But let us mask whether there is a creator or not. If not, how can he create things? ... Therefor before we can talk about creation, we must understand the fact that all forms materialise by themselves ... Hence everything creates itself without the direction of any creator. Since things createthemselves, they are unconditioned. This is the norm of the universe." (ch.2 NHCC, 1:46a-47b) -Quoted from Wing-Tsit Chan's, A source book in Chinese Philosophy, Princeton University Press, 1969). Chan is the translator as well as the editor.
In early Indian thought, thoughtful thinkers arrived at similar conclusions, You can find at least some of the strands of thought in the Wikipedia entry, entitled Atheism in Hinduism.
(Reference: https://en.wikipedia.org/wiki/Atheism_in_Hinduism