Where can see all non standart Entites?

for example : “_color” of light entity is not standart and not have level editor

Not sure what you are looking for.
What editor are you using?

If you want to know what entity is on which part of a map you can search with an editor, say Texpad, in the end part of a bsp .
There you’ll see after the bin part all entities and how they are arranged.
So a light with setting _color 256 128 0 will be red and _color 0 128 256 will be bluish green.
All other parts, like statics, will be there although you have to trace where their origins are.

I think he is writing about keys on entities which are not in the .fgd file, hence they are not automatically listed on the entity’s properties on the editor.

If it is that, there is no list of that, save for those which come from a mod, if the creator made such a list.