As far as I know...
DST has the following on the way:
Uncle Deadly and Pepe the King Prawn.
Sweetums and Robin the Frog Re-Sculpt.
Lips and Lew Zealand.
*Beauregard and Pops the Doorman, this 2-pack was rumored to be next in line, not sure if true or not.
After that, characters from Palisades Toys that DST still "could" include as part of their line.
The Snowths.
Thog.
Doglion.
Jim.
The Steel Rabbit (pack-in figure).
The Bust of Beethoven (pack-in figure).
The Japanese Cake (pack-in figure).
Link Hogthrob, I'd prefer him in casual/civilian clothes.
Dr. Julius Strangepork, I'd prefer him in casual/civilian clothes.
M.A.M.M.A. (pack-in figure).
The Male, Female, and Baby Koozebanian Creatures (pack-in figures).
The Newsman.
The Lobster Bandidos (pack-in figures).
Clifford.
Polly Lobster (pack-in figure).
Johnny Fiama.
Dr. Phil van Neuter.
Marvin Suggs & The Muppaphones.
Bernice the Chicken (pack-in figure).
Chucky the Dummy (pack-in figure).
Gaffer the Cat (pack-in figure, hopefully with the Beauregard/Pops duo).
The Java Muppets (pack-in figure).
Bernard the Ghost (pack-in figure).
Yorick, the blue skull from TMS (pack-in figure).
Sal Minella.
Pigs in Space 3-pack figures in uniform.
Vet's Hospital 3-pack figures in uniform.
Then there are the characters that DST could make that Palisades never got to, but in my somewhat-distorted mind's eye could be made using existing figures as customized base figures.
Bill, Gill, and Jill.
Constantine.
Mo Frackle.
Spamela Hamderson.
Hilda the Wardrobe Lady.
Beth Bear.
Bobo the Bear.
George the Janitor.
Harry the Hipster.
Mrs. Emily Bear.
Skeeter (grown-up version).
David Hoggselhoff.
Andy & Randy Pig.
Betina & Belinda Cratchit.
Yolanda the Rat.
Digit.
Astoria, Waldorf's Wife.
Annie Sue.
Betsy Bird.
Mildred Huxtetter.
J.P. Grosse.
The Moopets: Kermoot, Foozie Bear, Animool, Janooce, Miss Poogy, and Roowlf.
Wayne & Wanda.
Then there are others like Walter, Boppity, Gloat, Bobby Bensen, Nigel the Conductor, that "could" also be made by DST to further enhance the line. Just something that I thought I'd put forth given the comment of how DST "might" be running out of characters to add.