Here is a list of all vendor changes from 2018 to 2019.  It's now (hopefully) complete.

Note that this info is taken directly from the Exhibit Hall Maps.  Any info supplied in the comments I'll note in {}

New Vendors
Alligator Alley Entertainment
Angelarium {were part of the Art Show last year}
Anomia Press
AntiMatter Games
Argent Saga
Artists Of Magic
Beadle & Grimm’s
Bicycle
Blonde Swan Hats
Board & Dice
Brother International Corp
Certifiable Studios
Creature Curation

Dann Kriss Games
Draco Studios
Drew Baker
Eldritch Foundry
Epic Adventure Candles RPG Apothecary
Fernando’s Engravings
Feuerland Spiele 
Fog of Love
Forbidden Games
Funko

Geek Orthodox
GeekOn
Goliath
Gooey Cube
Grandpa Beck’s Games
Happy Baobab
Harebrained
Hobby Japan Co., Ltd.
Hobby World
Hub Games
Incarnate Games
itten

Jackbro and Animalcatraz
Judgement
KLASK
Knight Models
KTBG

Mercury Games
Midsummer Knight’s Dream
NecroMech
Netherhavyn Game Works
Nomnivore Games Inc
Oathsworn
Orange Nebula

Para Bellum Wargames
Parallel Games
Peaceable Kingdom
Penny Arcade
Play To Beat Brain Cancer
Pleasant Company Games
Project Genius
Rock Manor Games
RPG Coasters

S7 Games
Savagesparrow Studios
Shadow Squirrel Games
Shard Studios
Shenanigames
Square Enix, Inc
Stephen Najarian Illustration
Sweet Games
Systemic Games
Table of Ultimate Gaming
Tabletop Tycoon (was originally Tabletop Direct)
The Deck of Many
The Nuadan Chronicles RPG
The Rook & The Raven
Thompson Productions
TTCombat
U Gears US

Warhammer Age of Sigmar: Champions
Wattsalpoag
Wayne Reynolds
Weird Giraffe Games
Wyvern Gaming
YOKAGAMES

Dearly Departed Vendors
Action Sportscards and Collectibles Mall
Anime Palace
ARCHIVOS Story Development
Braine Games
Broken Dice
Card Caddy
Cards Against Humanity
Cartoon Passion
Cheapass Games {now part of Greater than Games}
Coffee Cake Gaming
Critical Role

Dante Slack
Dog Might
Eagle-Gryphon Games
Eggertspiele {now part of Plan B Games}
Et Games
Eternal Games
Fabled Realms by 4Ground
Funforge

Galactic Toys
Game Salute
Games Adults Play
God Hates Charades
Gold Baby Games
Griggling Games
Hawk War Games
Haywire Group {now part of University Games}
HeidelBÃR Games
HELVETIQ
Hi De Ho Magic
Imagine Nation
Inkwell Ideas
ION Studios - Retail Gaming Technology

Jordan Draper Games
Kids Table Board Gaming
Kommando Kilts
Lightseekers

Make Believe Games
Meta Arcade
Midnight Syndicate Soundtracks
Onyx Path Publishing

Passport Game Studios
POWER 62 GAMES
Pretzel Games
PulsArt Studio
Qmomo / VooDoo Baby
Ravendesk Games
ROXLEY
Rule & Make

Sensible Object
Set Enterprises Inc.
Spellforge Games
Spy Alley
Summon Entertainment
Table Forged
Tabletop Co-Op
The Blonde Swan
The Midsummer Knight’s Dream
TheWarStore.com
Toynk Toys
Tudor Games

Whimsy Works
Who North America
Wizkids

Name Changes 2018 -> 2019 (does not include capitalization changes, or inclusion/removal of things like "Inc.")
Adventure Scents -> Adventure Scents/Oddfish Games
Decision Games /Strategy & Tactics Press -> Decision Games
Glitch -> GlitchGear.com
Inside the Box Board Games -> Inside the Box Publishing
Mantic Entertainment -> Mantic Games
Mattel Games -> Mattel
Midclash Games -> Midclash
Oni Press -> Oni Press/Oni Games

Nigel Sade Fine Art -> Studio de Sade
Shadow Myths -> Shadowmyths
Spiel des Jahres -> SPIEL DES JAHRES E.V.
Spin Master -> Spin Master Games
The Game Center -> Asmodee
The ENnie Awards -> ENnie Awards
Tommy Castillo -> Tommy & Sammy Castillo
White Wolf Entertainment -> White Wolf
 

John Wick Presents is now part of Chaosium. They shared a booth last year with Indie Press IIRC.

Greater Than Games acquired Cheapass Games, so I'm guessing they'll be sharing a booth.

I'm rather shocked that cards against humanity is gone

Angelarium was part of the Art Show last year.

Ohh. Beadle & Grimm's. Gonna have to check out their (expensive) stuff. I wonder if I brought my DVD of Wing Command if Matthew would sign it.

Asmodee was always there they were just not labeled as Asmodee, but went by "Game Center"

I always joke about our Asmodee overlords, but that was always something that irked me, because it felt like I was being lied to or mislead in some way. When you went to the "Game Center" booth it was clearly all Asmodee products that didn't have their own booth but nothing said Asmodee.

Eggertspiele's NA footprint is now via Plan B games, so they'll be there (especially since they are releasing Era: Medieval Age and it'll be out at Gen Con by all reports)

Just added G-M

Haywire was bought by University Games, booth 2105 

Added N-Z.  List should be complete, please post any errors you might find, or helpful info as to departed vendors who are now part of other booths.

Sad to see Midnight Syndicate gone. I have a number of their CDs. Not only do we use them for our RPG games, but sometimes I just play them as background noise in the house.

No Hirst Arts, no WizKids, no Alea Tools :-(

This is great work!

Here's a few things that I know (or think I know):

Beadle & Grimm’s was there last year but wasn't on the list.

The Nuadan Chronicles RPG = Broken Dice

Onyx Path Publishing is supposed to be there; I'd bet money that they'll be in the White Wolf booth (but haven't confirmed it).  

Cards Against Humanity doesn't really need Gen Con anymore.  Just to sell product?  They can do that at Target for a much better margin.

Actually, they get much better margins selling directly at the Con.  They get 100% of the purchase price.  Selling through a retailer, they’re first selling to a wholesaler for maybe 50% of the retail price.