There are whole lot of dark corners of the 40K universe that we need rules for. Here’s were I would start if I ran GW Digital.
My self-inflicted restrictions for these are they either:
a) Already HAD rules in the universe at one point (and probably miniatures)
b) Don’t have rules but would require easy conversions (no new minis from scratch)
Genestealer Cult – We’ve all been begging for this list for decades. A fusion of IG and Tyranid elements, with Limos just for coolness points!
Adeptus Arbites – We ALREADY have models and had rules for a variety of units from Judges, to Enforcers, to Cyber-mastiffs, and even more.
Eldar Exodites – We have various Guardians, Eldar and Dark Eldar vehicles – to do a mashup with Dark Elves and Lizardmen dino beasties. Just give us some cool rules – we will convert the rest!
Lord Solar Macharius – I really really miss saying “put down the dice – I choose to Seize”
Mechanicus – For those not keeping track, we now have over a half dozen different Mechanicus units and a proto-army list in the Horus Heresy books. Come on GW Digital – this one is shooting fish in a barrel if they want those resin FW units to have sales increases of 2000%
Imperial Navy Forces – A ship-borne variant of Imperial Guard for all those Zone Mortalis or ship-board themed games. How cool would they be for all your narrative game ideas?
Eldar Naval Forces – See above, insert pointy ears and crystal poop (read xenology…)
Enslavers – Anyone remember these ultimate bad-guys who take over the enemy? They are a 40K Cthulu type ancient evil and had rules! ALL HAIL HYPNOTOAD!!!
Relictors – Such a great “Chapter on the Edge” who lost their former rules. Phil Kelly could knock out a set of rules over lunch.
DOOMRIDER – He does Cocaine! (how can he not have Vector Strike – think about it)
What did I miss?