The OpenGL 4.6 release has some interesting extensions promoted to core.
Including SPIR-V, now it's good to add to OpenGL ES.
Also following OpenGL 4.6 core extensions would be good to have in an OpenGL ES 4 release:
GL_ARB_texture_filter_anisotropic
GL_ARB_shader_group_vote
GL_ARB_shader_draw_parameters
GL_ARB_polygon_offset_clamp
GL_ARB_indirect_parameters