Jellicent and its pre-evolution were most likely inspired by the Nurarihyon, a jellyfish youkai that is either shown as a demonized jellyfish or as a jellyfish-like man who wears refined, sometimes regal, clothing. It is also possible that they was inspired by the Kurage no Hinotama, a sort of jellyfish-like will-o'-the-wisp.
Lucario appears to be based on the Egyptian god of funerals, Anubis, who has the head of a jackal. Anubis's role in Egyptian mythology was to judge the hearts of deceased souls based on their actions during life.
Seems kinda dark type-ish.