As the generations go on, some older Pokemon get new toys to play with, such as new evolutions, pre-evolutions, regional variants, Mega evolution, and Dynamax forms to name some. While getting something is better than getting nothing, there are still some Pokemon who got less impactful or insignificant things. A few examples that I can think of:
Corsola: the Galarian form did get some usage with it being Eviolite eligible, and while I love the concept and design of Cursola, it has been irrelevant since the day it came out. I wish it were better or more unique. I think a Ghost/Water or Ghost/Rock would have helped.
Stantler: Wyrdeer is a cool design, but outside of you riding it in PLA, nobody thinks about it. I think a few more BTS would have helped it stand out, especially against Farigiraf who became out in a similar time with the same typing.
Victreebel: I looooove the Mega design, but nobody uses it since it’s not good at all. From its promo and Dex entries, I was really hoping for an ability or move that would allow Poison-type moves to hit Steel types.
Jynx: no explanation needed here, but if you’re out of the loop, it got left behind after Smoochum. Since it’s one of the most disliked Pokemon in the franchise, I doubt it’ll get anything again, which I think is a shame.
Any other Pokemon you would add to the list? I again want to say that at least these Pokemon got something, while there are many that don’t have anything since their debut. Still, I would argue that these Pokemon will be further ignored and not become relevant ever again. Not every Pokemon has to be a standout, but if they’re going to give something to one, they should try to make it stand out.
EDIT: I’m highlighting Pokemon who DID get something after their debut, but did not get ENOUGH. I’m not focusing on Pokemon who haven’t gotten anything at all, that’s a separate discussion.