I tried a lot of shaders and ended up finding 5 shaders packs that seems to work well under Iris that were not listed in Iris/docs/supportedshaders.md
I tested the latest version of all listed shaders with the Fabric 1.18.2 and the latest Iris version.

SORA Shaders: Has a message saying it is compatible with Iris in the curseforge description.

Simplicissimus Shader:

Beyond Belief Shaders: Based of SEUSv11

Oceano Shaders 3.0:

RRe36's Shader: This shader is discontinued and will not have new updates, but RRe36's newer shaders all don't work in Iris. (Other than Simplicissimus, but I already listed it, and they look very different.)

Thanks for the investigation. SORA and Oceano were already listed, I added Beyond Belief and RRe36's Shader in 70f57b6, but Simplicissimus Shader doesn't work on current Iris: