BigMax
Fine Arts - Two hundred uploads with a score of over a hundred (Safe/Suggestive)
The End wasn't The End - Found a new home after the great exodus of 2012

So far:
 
GlancoJusticar 12  
Thelivingmachine02 5  
Ric-M 4  
John Joseco 4  
Megasweet 3  
Derpiihoves 3  
Ninjaham 3  
Sundown 3  
ManiacPaint 2  
Ross Irving 2  
Semehammer 2  
The Artrix 2  
Mauroz 2  
Shepherd0821 2  
Glasmond 2  
Scorpiordinance 2  
Cartoonlion 2  
X-Arielle, Gomigomipomi, Trinityinyang, Spindles, Ponideathmarch, Sallymon, Inkintime, Hazurasinner, Moronsonsofboron, Pluckyninja, Suikuzu, Atryl, Vasira, Apples 1
 
I’m not surprised to see Glanco on top.  
But there are some heavily under-appreciated artist there. Like Gomigomipomi, Sallymon, Hazurasinner and Suikuzu.
 
Seriously, guys?
Jellypony

Glancojusticar for me, hands down.
Ferrotter
The End wasn't The End - Found a new home after the great exodus of 2012

Cartoonlion, because I don’t particularly care for humanized MLPs in the first place. But Futashy is funny as hell, which matters more.
BigMax
Fine Arts - Two hundred uploads with a score of over a hundred (Safe/Suggestive)
The End wasn't The End - Found a new home after the great exodus of 2012

But I still keep forgetting some, for example ManiacPaint and Suikuzu…
BigMax
Fine Arts - Two hundred uploads with a score of over a hundred (Safe/Suggestive)
The End wasn't The End - Found a new home after the great exodus of 2012

Glanco is on the top, I think.  
With Ric-M, Gomigomipomi, Derpiihoves, MoritoAkira and HazuraSinner close seconds.  
Other good artists include John Joseco, Megasweet, Ninjaham and TLM02.
Background Pony #C862
Derpii because he’s style of drawing appeals to my weeabooish self.JJ is too much sameface
dt
Diamond Tiara's Diamond Tiara - Derpi Supporter
Diamond -
Not a Llama - Happy April Fools Day!
The 1% - Uploaded 1% or more of the site's images
Happy Derpy! -
Derpibooru Premium - Learn about the benefits of subscribing to Derpibooru Premium membership at https://derpibo
Perfect Pony Plot Provider - 150 uploads with over 350 upvotes or more (Questionable/Explicit)
Fine Arts - Two hundred uploads with a score of over a hundred (Safe/Suggestive)
Since the Beginning  -

No Thank You
@dt
 
Y’know, I’d probably put tcun above everyone if he(?) ever draws more from this show.
Uberhooves

Don't acknowledge please
I have to say JohnJoseco, mostly because of his amazing art involving multiple humanized ponies
dt
Diamond Tiara's Diamond Tiara - Derpi Supporter
Diamond -
Not a Llama - Happy April Fools Day!
The 1% - Uploaded 1% or more of the site's images
Happy Derpy! -
Derpibooru Premium - Learn about the benefits of subscribing to Derpibooru Premium membership at https://derpibo
Perfect Pony Plot Provider - 150 uploads with over 350 upvotes or more (Questionable/Explicit)
Fine Arts - Two hundred uploads with a score of over a hundred (Safe/Suggestive)
Since the Beginning  -

No Thank You
Ric-m.
Retl
Lunar Supporter - Helped forge New Lunar Republic's freedom in the face of the Solar Empire's oppressive tyrannical regime (April Fools 2023).
Bronze Bit -
Emerald -
Happy Derpy! -
Bronze Supporter -
Artist -
The End wasn't The End - Found a new home after the great exodus of 2012

Megasweet got me into humanized at all.
Balloon_Party

Hmmm, gotta say JJ. He was my first humanized artist that I remembered in a positive way. Keeps the essence of the show, but humanized.
Gliding2hell
The End wasn't The End - Found a new home after the great exodus of 2012

Apples
Nopony_In_Particular
The End wasn't The End - Found a new home after the great exodus of 2012

Glanco, Sundown, Glasmond, Ninjaham, Theartix, Scorpiordance, Atryl, and Vasira are among my favorite humanization artist.
The Smiling Pony
Cutest Little Devil - Celebrated the 14th anniversary of MLP:FIM!
Rainbow Rocks 10th Anniversary: Sonata Dusk - Celebrated the 10th anniversary of EQG Rainbow Rocks!
Celestial Glory - Helped others get their OC into the 2024 Derpibooru Collab.
Nightmare in the Moon - Had their OC in the 2024 Derpibooru Collab.
Pixel Perfection - I still call her Lightning Bolt
Silly Pony - Celebrated the 13th anniversary of MLP:FIM, and 40 years of MLP!
Shimmering Smile - Celebrated the 10th anniversary of Equestria Girls!
Solar Hero - Went above and beyond for the Solar Deity, drawing from the power of the sun itself to bring balance to the fight against the Lunar Insurrection (April Fools 2023).
Roseluck - Had their OC in the 2023 Derpibooru Collab.
Flower Trio - Helped others get their OC into the 2023 Derpibooru Collab.

( ͠° ͟ʖ ͡° )
thelivingmachine02, Glanco and Ric-M are the names that pop up first; characters translated well and not sexualized is yay.
Iristrismegistus
Perfect Pony Plot Provider - Uploader of 10+ images with 350 upvotes or more (Questionable/Explicit)
Bronze Bit -

MEGASWEET
AzuNyan

Shephard0182
Background Pony #0FFC
Mauroz, derpiihooves, and suikuzu are really good. John Joseco is okay at times. I don’t like Glanco’s art that much. If anything, arucardPL’s and MoritoAkira’s are the cream of the crop in terms of humanized works.
HydroSpanner
Non-Fungible Trixie -
The End wasn't The End - Found a new home after the great exodus of 2012

Glanco and Maniacpaint more or less.
MGB_GT
The End wasn't The End - Found a new home after the great exodus of 2012

It’s difficult as even the worst have done some good images.
 
At a push i’d say pluckyninja is alright as is livingmachine02. Glanco is good as well. Too bad there’s so much to list but that’s a good thing right?
 
I prefer artists who can make a subject alluring (sp?) without it being dirty myself. If some rules are broken for sake of style i don’t mind too much.
Step-chan
Lunar Supporter - Helped forge New Lunar Republic's freedom in the face of the Solar Empire's oppressive tyrannical regime (April Fools 2023).
The End wasn't The End - Found a new home after the great exodus of 2012

Not sure who mine is.
Who cares the pony

REAL LIFE
 
idiots
 
Go watch anime for that dumb ass school shit
1658489721584

semehammer
Background Pony #637C
everyone who can make a somewhat plausible humanization is ok in my book.
Gentle Coltte of Leisure
The End wasn't The End - Found a new home after the great exodus of 2012

Now... fart.
Do I even need to say it?
 
full
 
Ross FTW  
(Even if these designs are horrifically outdated)
delatin

Maniacpaint. Hands. Down.