Great choices. In particular RB Lapras might be its best sprite ever in my opinion. Really nails that calm, serene look that is perfectly on brand for it as a Pokémon. And while Kingler is wrong as you pointed out, it always looked very threatening to me as a kid.
On the topic of the Nido's, I really like Nidoking's RB sprite which gives Gyarados a run for its money as the best overall RB sprite in my opinion:
Thanks. And I agree about Nidoking in R/B, it is a really good sprite.
And I never noticed Porygon's Crystal animation. Probably because you never encounter it in battle or in the wild in that game as far as I recall. That's a fantastic touch for "The Virtual Pokémon".
Not sure if I ever saw it in the actual game either. 5555 coins, post-game only, and you are likely going to evolve it, so I guess it is easy to miss its animation.
And I like Vaporeon's Gen 5 sprite, especially its body facing away from you. But I prefer its Platinum sprite. I see Vaporeon as a calm rather than playful Pokémon, similar to Lapras, which is why I prefer its expressionless sprite in Platinum:
Fair enough. I prefer its Gen 5 sprite as said, but I agree that its Platinum sprite is really good as well, second best one IMO.
And now, time for some more of my favorite sprites. When looking up sprites I like, I often found it hard to draw the difference between sprites I like and Pokémon I just really like. But I tried my best to focus mostly on the actual sprites themselves, not on the Pokémon. There’s none from R/G, and that’s because I did honestly not found a single sprite from these games that I really liked. Sad as it is to say. But I guess it isn’t too surprising since the sprites of R/G are generally considered infamously bad, which I mostly agree with. There's none from D/P either, I guess I just prefer the Platinum sprites for the most part (and some from HG/SS too).
Anyway, here are some more sprites I like, mostly from Gen 3 and on this time.
Cubone is another one from R/B that is pretty good. The pose is a little weird, but other than that, I think it is great.
I really like Crystal Raikou. Partly because they fixed the wrong design it had in G/S, but even if we look past that, it is still a really good sprite. I like Hitmontop as well, especially the animation which creates an illusion of it spinning really fast, which is super cool.
Skitty is always super adorable, but I think its original sprite from Gen 3 is the cutest of them all.
From FR/LG, those are just two really good sprites if you ask me. Not much more to say here.
The Emerald animations were a bit more advanced than the ones in Crystal, but still quite simple. Though some of them were a bit more complicated. I really like the animation for Pidgeot, it does a quick spin in the air which is really cool. Gastly turns black, which is neat. I also like ones that flash, notably several Electric-types such as Magneton and Raikou. Milotic is similar since it turns blue. I also like Kecleon which turns invisible, it was neat since being able to turn invisible is one of Kecleon’s themes.
From Platinum, I really like the ones that have cool poses, notably several of the Sinnoh Pokémon. Infernape is excellent, as has been said before. But I think Staraptor, Garchomp and Magmortar are really great too, they all look so cool.
From HG/SS, Seel and Dragonite are my favorites. Seel is great just like in FR/LG (it even has the same pose) and is super adorable, which is very suitable since it is one of the very few cute Pokémon from Gen 1 IMO. Dragonite is just perfect, I think HG/SS has the best Dragonite sprite in the series.
I think Gen 5 has the best Suicune sprite in the series. While it was quite good in HG/SS as well, I think B/W made it even better. Gen 5 also gave new sprites to a majority of the Gen 3 Pokémon (which led some fans to believe that we would get a R/S remake in Gen 5), and I think most of the Gen 3 sprites in Gen 5 are excellent. Manectric, Salamence and Latias are three of my favorites (though I might be biased towards Latias since I just love Latias in general). I also think the sprite for Tyranitar in Gen 5 is its best sprite. While some of its previous sprites are solid too, notably in Gen 4, they really made it perfect in Gen 5.
Unpopular opinion perhaps, but I really liked the animated sprites in Gen 5. My favorites are those who really take advantage of constantly being in motion, notably several from Gen 5. I really like Spiritomb, it looks a lot better with its body constantly spinning. I’m glad this was kept in its 3D model as well. I really like Lilligant too, it is super cute (but I think Lilligant is always cute, so I might be biased). Cofagrigus is also great with how it is hiding and then coming back. I like the Klink line as well, they are great when they are always spinning (and I’m glad that they kept that in their 3D models too). Lastly, there’s Reshiram and Zekrom. The way they “light up” in their animations is just so amazing and I love it.
This is not a sprite, but I’m including it anyway. I love Magikarp’s 3D model. Everything about it is perfect. It captures the essence of a weak, useless, pathetic fish so flawlessly, while also giving a relaxing feeling. That’s the third time I’m saying that here on the forums, but I guess it can’t be said too many times.
So yeah, those are some of the best sprites (and one model) IMO. There’s probably a lot more but this what I have for the moment at least. Might post here again later if I can come up with anything more.