Replicating MMD look in Blender
For easy preview, you can use Workbench. Set lighting to Flat and color to Texture. You can also set View Transform to Standard.
It is the easiest way to preview MMD models but unfortunately spheres & toon textures don’t work. Also, there’s no transparency support.
Eevee supports full shader, but you have to setup toon shader instead of realistic shading.
This is an example of toon shader. (before/after)
You can use MMD Tools Helper to convert MMDShaderDev to toon shader.
There are other toon shaders for Blender:
credit: Lisa, Sucrose, Lumine (Genshin Impact), カルも式初音ミク