My order would probably be this (I know you’ve said just Neo, but there aren’t too many cards with Shining in the name, so I’ve just included all - but feel free to focus on just the underlined ones from the Neo era ):
Shining Gyarados (Neo Revelations) - S tier
Shining Mew (Japanese-exclusive CoroCoro promo) - S tier
Shining Magikarp (Neo Revelations) - A tier
Shining Kabutops (Neo Destiny) - A tier
Shining Steelix (Neo Destiny) - A tier
Shining Imakuni? (Japanese-exclusive 018/P promo) - A tier
Shining Genesect (Shining Legends) - A tier
Shining Tyranitar (Neo Destiny) - A tier
Shining Raichu (Neo Destiny) - B tier
Shining Ho-Oh (SM70 promo) - B tier
Shining Charizard (Neo Destiny) - B tier
Shining Rayquaza (Shining Legends) - C tier
Shining Celebi (Neo Destiny) - C tier
Shining Mew (Shining Legends) - C tier
Shining Celebi (SM79 promo) - C tier
Shining Noctowl (Neo Destiny) - C tier
Shining Mewtwo (Neo Destiny) - C tier
Shining Lugia (SM82 promos) - C tier
Shining Volcanion (Shining Legends) - C tier
Shining Jirachi (Shining Legends) - D tier
Shining Arceus (Shining Legends) - D tier
Although I always liked the triple-star rarity of the Neo Destiny Shining Pokémon, I’ve never been the biggest fan of their artworks if I’m being completely honest.
As for Shining Gyarados, I consider it one of the best artworks of the TCG.
I’ve come to the conclusion that I don’t really care for any of them. Sure, Gyarados and Magikarp are decent by default and other than Steelix and Mewtwo I don’t hate any of them but it just feels like I’m going through the motions whenever we rank them. I do enjoy the colors on the Raichu, probably my favorite from Destiny, which probably would be Tyranitar if it wasn’t for the Fire energies. If I was still spending money I’d rather buy Base Blastoise or Ruby Sapphire Dustox 50 times over before buying any of them.