>>33118403-Wind
similar case of redundancy here, as Flying currently covers any unflavored wind-concepts. But in addition to the literal wind-aspect of it, the Wind type as I envisioned it would also include any strong association with agility (hence also including PKMN like Arcanine, Dodrio, Ninjask, the beasts), as well as using means of affecting the opponent at a distance, either by spreading spores/harmful particles or gases etc. (hence Weezing, Aromatisse, some of the butterflies/moths). Moves would include things like Gust, Extremespeed, Hurricane, Razor Wind, Air Slash, Smokescreen, Defog etc, while also having the gimmick of there being a diverse selection of dual-type moves with other types (Leaf Storm, Fire Spin, Whirlpool, Blizzard, Ominous/Silver/Fairy wind, etc.)
-Plastic
this is the type I'm least satisfied about the name, but I just can't come up with something better that doesn't do a worse job at representing the type.
It's basically everything that seems at least partially unnatural (but not in a mystical, paranormal way, while also being distinct from alloys/machinery), as well as amorphous creatures (irregular/changing body structures) and being able to grow new limbs.
I started doing this one as a joke, but was legitimately surprised in how big and diverse the potential application was.
Moves are less clear-cut and would certainly need new ones (not like Fairy relied on retconning old moves either anyway), but some examples would be Substitute, Recycle, Minimize, Self-Destruct, Bind/Constrict, Thrash, Tri-Attack..
-Sound
probably the most popular fake type out there. Just felt like I needed to include it, since I came across plenty of PKMN that were screaming for it, at least as much as any of the other fake types above. The concept is straightforward and already has some presence in game mechanics.