Particles Box is a Blender add-on from fffaaa12 that gathers a range of particle and atmospheric effects into a single package. The set spans weather elements such as fog, rain and snow, leaves, dust and fluff, plus butterflies and flies, giving you multiple effect types to work with inside Blender.
The add-on is compatible with Blender 4.2, 4.1, 4.0 and 3.6, and is registered as a Blender extension. It ships with documentation, and a demo video is available.
Available through the superhive library, Particles Box is offered under a royalty-free license. It has been published for almost two years and has recorded more than 300 sales, alongside a handful of user ratings. It's listed here as free, with licensing details available on the developer's page.