In my case it's the normal type, I always try to take one with me in the team because I really love it.
They are Pokémon that hit neutral to almost all the type chart and the truth is that this is more valuable than one might think.
Normal-type Pokémon learn everything, have a wide repertoire of moves. They are also usually quite powerful Pokémon and you have many to choose from:
Need an offensive Pokémon? Tauros, Stoutland, Zangoose…
Need a defensive Pokémon? Snorlax, Blissey, Miltank…
Besides, in older generations they also helped you to fly (Pidgeot, Noctowl, Swellow, Staraptor, Unfezant) or helped you with HM's (Bibarel, Watchog).
by Ivi_Crispa