I was a proponent for Light-type based on EM radiation and pokemon that can emit such
>Retyped pokemon
Starmie (Water/Light)
Lanturn
Ampharos
Luxray
Lucario
Necrozma
Porygon, since it's a physical hologram
That mushroom thing from Alola, possibly, but Grass/Fairy is fair for it
>Moves that can be retyped
Signal Beam
Solarbeam
Tail Glow
Flash
Double Team
Laser Focus
Mirror Shot
Lock On
Reflect
Light Screen
Spotlight
Moonlight
Morning Sun
Sharpen
Luster Purge
Flash Cannon can be retyped too but I excluded it for reasons
New Moves
>Lightspeed
Light-type Quick Attack
>Photon Cannon
Light-type Overheat
>Solid State
Light-type Crunch
>Invisibility
Light-type Protect
>2x Damage Against:
Fairy (Nocturnal creatures that don't like to be spotted), Ghost (Same), Electric (creates interference)
>.5x Damage Against:
Rock (Refracts or obstructs), Ice (Refracts), Bug (Bugs swarm light sources)
>0x Damage Against
Grass (Photosynthesizes)
>Resists:
Fairy, Ghost
>Weak to:
Bug, Grass
It's entirely possible to make it work without stepping on Electric, Psychic or Fire. Moves/mons that only generate electricity stay electric. I didn't retype anything Fire. Psychic can remain the psychic energy/telekinesis/telepathy type, but moves that create illusions, hard light, or photons would be light. Also logical way to make the type chart a little more balanced
Only other argument I see is that people don't want a "Holy" type in Pokemon when they have Psychic so my version sidesteps the issue entirely
