I will continue to add enthusiasm for an Endless RPG. "Endless Adventure" would be a great way of keeping the naming convention going.  My personal preference would be in the style of single player RPG with party recruitment and some interesting crafting mechanics (to play with the established resources that we already know in the setting).  Add in some light planet hopping or at least heavy use of the science-fantasy theme they already have going.  Include some multiplayer cross-over areas for things like dueling, playing mini games with collected components in-game, or completing special quests and you could have something unique.

To add another genre opinion: Metroidvania.  "Ruins of the Endless", a game where you are an Academy recruit that has found themselves entering into an ancient Endless vault and must explore to find access to it's core.  You could play with using Dust to power abilities and gaining various pieces of equipment while fighting against twisted buried abominations and competing raiders trying to beat you to the core.

Falkner wrote:

Endless City Builder.

Like Banished? I could get into this. I love the infrastructure of all the different races.

Craver FPS like in the ES2 Craver's intro :D

Endless City Builder.

Graphic wrote:

Endless War.  A military game with industrial technology (1860-1944 or so), but in a fictional world with fictional nations.

Yes.  Much like the Total War series... which I do enjoy, but can never get enough of.  I would love to see Amplitude take this on!

I've always pondered the idea of an Endless Space RPG. I'm one of those nerds that read every discription of everything in that game, and I've always thought that whoever writes those, could write a compelling RPG, not to mention the cast of races, and the general feel of the game, its more of a modern, technophilic, and in some places, very transhuman feel, almost hard sci-fi with its adoration of cool tech, but lacking the strict scientific basis that hard sci-fi obsesses over. This alone makes me think that and Endless Space would be a compelling enough of a world to quest in. Hell it inspires RP in off topic...

Design wise, I'd say that Endless Dungeon is a good start, it was an oddity of a game, very original in its mechanic set, and still really fun to play, but its like really light on the depth. It had a basic set of stats, and really quick decision making when it came to kit and class. I'd say for an RPG, I'd want it to go pretty deep, as deep as their 4x can get. Focus most of the design work on a compelling, interesting, very indepth roleplaying mechanic set ala Pen and paper, or CRPG (Hell it'd probably be best as a CRPGish game) and then brush over the story and the world with the usual Endless flare. Of course things are more complex than that, but I feel it'd be successful.

Anyways, post your ideas

I think an RTS would be awesome!!! Similar to Rise of Nations (where you start out in almost Stone Age then advance to whatever...), maybe start out in Endless Dungeon/Legend tech stage and advance to the end tech of Endless Space/ES2.

While I am thoroughly enjoying the development of Endless Space 2, I am also already very excited about the possible next addition to the Endless universe that is not a sequel, but something entirely new.

And indeed, an Endless RPG would be great. I think it would also be interesting to see an RPG combined with a Survival game. Or maybe call it a Survival game that is very story-/quest-driven …

Another thing that could be interesting would be a SciFi/Fantasy City Building game in the Endless universe. It could feature some 4X elements with a new livery, maybe limited to one or only very few cities. Politics and how to handle the needs of different factions inside the city could be an important factor in this.

But what I would most love to see is a digital realisation of a Living Card Game. I am currently very much enjoying the Lord of the Rings and A Game of Thrones LCGs by Fantasy Flight Games, and I think an Endless version of that would fit right in. Different playable major factions like in A Game of Thrones, or FIDSI could be the equivalent of the spheres from Lord of the Rings, there could be neutral allies from minor factions. Maybe it could be made more story-driven than a physical card game easily allows. Also, the concept of Living Card Games would be ideal for endless DLC expansions and modded content … and it would be a smaller game like DotE, which might be nice again.

Hmm i would love to see a 3D space battle game, not a 4x like Endless Space but more like Homeworld, where you control your ships, they can move on the 3 axis, with news ship category, carrier, asteroid collector, supercarrier, frigate, defense station, mothership.

This combine with their beautiful ship model from Endless Space 2 could help them with their narration with a full solo campaign 

For now, I really think they should focus on one particular genre until they're really well recognized by the gaming community; Even if their fan-base is slowly growing and they manage to acquire a pretty big and new publisher. While "Dungeon of the Endless" shows that they can do pretty well in other scenarios, I think it'll be wise to focus on maintaining a steady reputation before expanding their line of products. 

However, if we just instead talk about what genre I would like to see and ignore what I just said :p , I would want to see them do a FPS in the style of Section 8. Ignore all their experiences of turn-based strategy games and do something completely new just because the trailer for the Cravers was good.

Endless War.  A military game with industrial technology (1860-1944 or so), but in a fictional world with fictional nations.