Generally, I see a lot of talk about which of GRBY/Gen I's Pokemon sprites were the worse, with many different opinions.
But maybe instead of finding the sprites you find to be the 'worst', why not take a moment to appreciate some things in the games by saying which sprites you find to be the best or simply like for something different?
I have to admit that as much as I love Gen I, there are some sprites that I'm not too fond of, but I do have my favorites. I've personally always liked Blue's Nidoqueen, Blue's Dragonite, Green's Porygon and Green's Mewtwo.
I guess I could also say that the majority of the Pokemon sprites in Yellow were also good. Not all, but the majority of them. They were a vast improvement. (Especially Moltres' sprite...)