There are cool entries, there are weird entries - then there are the ones that speak to your soul a certain way. What are those for you? There are many for me, but my personal favorite is Alolan Ninetales from Ultra Sun. (image from Bulbapedia)
"Whismur is very timid. If it starts to cry loudly, it becomes startled by its own crying and cries even harder. When it finally stops crying, the Pokémon goes to sleep, all tired out."
Komala: Sun: It is born asleep, and it dies asleep. All its movements are apparently no more than the results of it tossing and turning in its dreams.
"This Pokémon adeptly flies from branch to branch in trees. In a forest, no Pokémon can ever hope to catch a fleeing Grovyle however fast they may be." "Despite its small body, Totodile's jaws are very powerful. While it may think it is just playfully nipping, its bite has enough strength to cause serious injury."
"It is virtually worthless in terms of both power and speed. It is the most weak and pathetic Pokémon in the world." Yeah sounds about right.
The Pokédex entry for the Alolan vulpix of Ultra Sun: "If you carelessly approach it because it’s cute, the boss of the pack, Ninetales, will appear and freeze you." The boss Ninetales is literally anyone else around me, for some reason they all think I'm cute. Gah.
The Pokédex entry for Mankey from Pokémon Sun kinda speaks to me. It can spontaneously become enraged. Everyone near it clears out as it rampages and the resulting loneliness makes it angrier still.
Piloswine's D/P entry: I have thick, long hair that gets in my eyes frequently. I also have a sensitive sense of smell so very accurate.
Minccino from Ultra Sun version -“A clean freak that will not allow even the slightest mess, it uses its tail like a mop to thoroughly clean any and all filth.”