Geometry nodes presets to generate Brownian motion in multiple ways:

Follow single Brownian Path:
- Generate a single Brownian path in confinement or not.
- Make the particle follow the path while rotating.

https://www.youtube.com/watch?v=Y8qy5Cd9KFk&embeds_referring_euri=https%3A%2F%2Fcdn.iframe.ly%2F&source_ve_path=MjM4NTE

Follow Multiple Brownian Paths:

• Generate and Follow Multiple Random Paths

https://www.youtube.com/watch?v=2_o7B5KQnM8

- Multiple Brownian Paths Confinement.
- Follow Multiple Brownian Paths Confinement.

Simulations: Simulate multiple particles in confinement.

https://www.youtube.com/watch?v=VVgVeImXlDU&embeds_referring_euri=https%3A%2F%2Fcdn.iframe.ly%2F&source_ve_path=MjM4NTE

Note that collisions occur only to the collision object. There are no collisions between particles. However particles can be pushed apart by the "Relax Position or Push Overlaps" check.