Continuum RT (B13 to B15) - Download [1.20.1+]

Continuum RT is by far the 2nd best ray tracing shaders for Minecraft, and the heaviest one as it's astonishingly demanding to any computer so take your precautions before applying this beast. the special about Continuum RT is that it ray trace everything unlike most of the shaders, and have an innumerable amount of settings you can tweak to make it look even better or to actually improve the performance because the default settings are a bit overkill and bumped, you can find how to make it faster on this video.

The Continuum RT is designed and built for Stratum texture pack since that resource pack belongs to the same company as Continuum RT, so it'd make a lot of sense if you paired with Stratum, The vanilla textures also look good with that shader but I just find POM to be a very useful feature to have a long side ray tracing. The new temporally integrated cloud lighting system allows the developers to remove many of the approximations previously used in clouds. Now they simulated in and out scattering properly through every pixel of the clouds, giving unparalleled detail and realism.

I was jaw-dropped when seeing the shader at its full potential using it alongside stratum, so I'm not regretting paying for this one, neither should you!