A great one would be Leauge of extraordinary gentlemen (the graphic novels) their very mature story's and many of the charscters are from victoriab literature similarly to TWAU so there's plenty of room for original characters to do with as they please (die horribly in your arms). The story's also involve lots of diologue for character development as well as violent fight scenes fitting right in with telltales formulae.
However after watchmen and v for vendetta I don't think Allan Moore is going to allow any more licenses of his stuff any time soon :/
Tbh though I think telltale have got enough series to work with I think for now they should continue with game of thrones, make another walking dead (haven't played seasson 2 but 1 had so much feals) and make a the wolf amoung us seasson 2! Seriously the gritty noir mood was awesome and they left us on such a cliffhanger

just make a sequel to walking dead i dont want anything else than a season 3

A new Discworld adventure. I remember when I played the old Discworld point-&-Click game with Eric Idle as Rincewind and the detective-themed Discworld Noir. 

.hack
SAO
Kingdom Hearts
Pokemon
Fire Emblem
Marvel/DC

Bible Black.

Queen's Blade.

You know, make hentai into quirky adventure games.

Futurama, since it's probably the last chance they'll have at coming back.

Or at least put Bender in a new Poker Night At the Inventory game. 

Hack/Slash
Hunger Games: The First Game
Lord of the Rings

Space Quest, if their Monkey Island attempt is anything to go by.