Another "camp" is panpsychism, which is often seen as a polar opposite of materialism. David Chalmers and Philip Goff are the two most prominent people pushing it.

They espouse consciousness or subjective experience is fundamental and contained in all matter.

There's a long history of anti-dualism in Kabbalist traditions, Christian Mysticism and Gnosticism.

For example, the Gospel of Thomas sayings #3, #77 and #113.