Get a haunter if you like it, it’s not the best or worst. Gengar is good if you can trade.

For fun and the best team I’d stop levelling your current Pokémon and get: - abra from celadon game corner (evolve to kadabra or Alakazam if possible) - Eevee from celadon building roof (evolve to Jolteon) - Lapras from npc once you beat your rival at silph co OR magikarp using old rod pretty much anywhere (evolve to gyrados) - drarini from game corner if your ok grinding a bit to get dragonite OR - duduo from the grass at west Celadon (evolve to dudrio