You have several options:
Okay, lets get to the comparison scene, shall we? Also, keep in mind that I am comparing only the "Good" Ghost-types as it's what OP asked for. Not all ghost-types are here.
Chandelure
Availability: Mid-game as a Litwick.
Pros:
Very good offensively, with a whopping 145 Base SpA
Access to the beloved Will-o-Wisp and Hex combo
Has many, many great STAB moves, including the one mentioned above as well as some more, such as Shadow Ball and Flamethrower
Good defenses, both being 90, allowing it to tank hits even super-effective ones
Decent Speed of 80 base. That, if trained enough, can outspeed and sweep
Cons:
Dusk Stone can be a pain to find
Litwick isn't that useful at first, forcing you to use Exp. Share on it
Evolves very late
Drifblim
Availability: Late-game (postgame?)
Pros:
A massive ABSOLUTE TANK with a whopping 150 base HP
Can get pretty offensive with 95 Base SpA
Access to good STABs like Shadow Ball and Ominous Wind
Access to the classic Stockpile-Swallow set
Access to Recover and Toxic, two classics on a Staller
Cons:
Mediocre stats overall
Not that good to use in a long run
The game is basically "Hyper-offense is my way!", and while it is certainly a little offensive, its just not that strong
Often relies on set-up to sweep
Jellicent
Availability: Early as a Frillish
Pros:
Huge HP stat, allowing it to tank a few hits
A good Special Tank, supported by the 105 Base SpD and 100 base HP
Access to Shadow Ball and Scald, two good STABs
Can be used as a fodder for surfing
Cons:
Mediocre overall stats
Not that good offensively. More of a tank, which isn't prioritized much in-game
Only serves as a surf-holder, when there are certainly better surf-holder
Cofagrigus
Availability: Early-Mid-game as Yamask
Pros:
A multi-tank with a whopping 145 base Defense and 105 base SpD
Pretty good offensively with a good 95 base SpA
Access to Shadow Ball, an amazing STAB
Access to Ominous Wind, a good STAB that may induce stat boosts
Cons:
Mediocre stats outside of Defenses and SpA
The best as a hazard/Toxic setter, both of which isn't prioritized much in-game
Golurk
Availability: Late-game as a Golett
Pros:
MASSIVE Atk Stat
Good ability in Iron Fist, making it utilize -Punch moves well
Access to Fly, making you able to travel around the region
Utilizes Fly well in battle
Cons:
Very slow
Mediocre stats outside of Physical Attack
Has a poor ability in Klutz. Good luck finding Iron Fist
So, in conclusion: Out of all the Pokemon provided here, I recommend Chandelure, Cofagrigus and Golurk the best.
Chandelure @ Choice Specs/Any
Ability: Flash Fire/Flame Body
Recommended Nature(s): Timid (+Spe -Atk)/Modest (+SpA -Atk)
- Shadow Ball/Hex
- Flamethrower
- Will-O-Wisp
- Filler
Cofagrigus @ Any
Ability: Mummy
Recommended Nature(s): Modest (+SpA -Atk)
- Shadow Ball
- Protect
- Toxic
- Filler
Golurk @ Choice Band/Any
Ability: Klutz/Iron Fist
Recommended Nature(s): Jolly (+Spe -SpA)/Adamant (+Atk -SpA)
- Shadow Punch
- Thunder Punch
- Brick Break/Superpower/Filler
- Filler
However, If you like the other two better, then go on. Anything goes in game so it won't that much of a hassle.
Drifblim @ Leftovers/Choice Specs
Ability: Aftermath/Unburden
Recommended Nature(s): Modest (+SpA -Atk)/Timid (+Spe -Atk)
- Shadow Ball
- Recover
- Stockpile/Protect/Filler
- Filler
Jellicent @ Any
Ability: Water Absorb/Cursed Body
Recommended Nature(s): Modest (+SpA -Atk)
- Surf/Scald
- Shadow Ball
- Recover/Filler
- Filler
Hope I helped!
