I'll start.

I think for me Poison is, without question, the greatest and best-designed type. For better or worse, they're extremely balanced, and utilize their status condition far better than Fire, Electric or Ice do theirs. Their theme is excellent, and realistic in a way that is barely seen anywhere else. Each line manages to present the theme in a new and innovative way while still remaining in-keeping with the family, creating a perfectly diverse cast of mons, both likable in their own way and also likable as a whole. SM has also provided great additions to the type in Salazzle, A-Muk, Toxapex and Nihilego, who, while its status as a legendary or non-legendary is debatable, is unarguably a special mon as it's the only plot-important UB, partially putting the no poison legendary meme to rest. I'd say this is the best gen for Poison mon-wise since 1, so it's definitely happy days. Just a shame about the boy Gengar.