|Hey, you aren't Cadians...|
SO Allies really opens up A WHOLE HEAP TON of opportunity for the player to create fluffy, effective, and characterful armies. I will give you a BUNCH of examples (as you will see IG is a critical factor for alot of these). The only thing I wish there was was a FW allies chart as well so we could see the level of alliance their army lists have.
2- Space Wolves- remember the days of old when they could take Leman Russ Battle Tanks, a tank named after their very primarch? Well those days have returned. By simply including a squad of vets and a IG HQ (Lord Commissar or Primaris Psyker) you can get up to 3 LR in a single choice. And if you model the guard effectively, you could make them like wolf scouts, or even use wolf scouts as the base and equip them with Lasguns, so you wouldn't even be using IG fluff wise and could claim it is a pure SW force, just utilizing 2 codicies.
4- Ork Looted and Slave Army- Use IG for access to vehicles. Turn the infantry choices into haggard looking slaves. Really opens up vehicle selection, and can give some non-open topped transports to Orks. I'd like to see a sentinel built with an ork pilot now.
5- Exorcist SM- So exorcist SM are suppossed to be a new type of Daemon Hunter, created though ritual possession of the novitiate and exorcism of the daemon through their will alone. Of course they guys would work with GK and Ordo Malleus elements (and are actually monitored closely by them). Through in an inquisitor and some GK forces to an SM and you really have the feel of the force.
6- Chaos Renegades/Cultists- IG + CSM or Chaos Daemons and some chaos modelling really makes the force as chaotic as can be whilst demonstrating that Chaos is more than just the elite forces playable in the game as of now. You could even claim the CSM HQ to be the warband's warlord. Perfect way to play Alpha Legion as well.
|Chapter Master Leonidas with the Banner|
8- Exodite Eldar- Dark Eldar and Eldar make the perfect combination to create exodites. Really comes down to modelling and unit selection, but a very potent and fluffy combination
9- Harlequin Force- Really DE with some Eldar in it, probably rangers and some jump infantry or vehicle or bike support, and I think you could craft a seemingly perfect harlequin force.
10- Mechanicum Army- Necrons and IG combined for this once. Most likely an IG base with necron elements added, though thinking about it, you could just use alot of Necrons and then IG for their vehicles. But this is the only obvious way to me to make the Cyborg army.
12- Chaos Legions- You can do any of the Chaos legions with the application of the correct daemons from their codex. Really nice because of the ability to unlock and take the greater daemons as an ally HQ or even 2 lesser ones as one Force Org slot. And then you just take the appropriate troops and elites, troops or fast attack. OR you can take a Daemon Prince from CD that feels more like a DP dedicated to his god than the CSM one does.
13- Kroot Mercenaries- Well really any codex that can take Tau as an ally can just buy a bunch of kroot for their list and BAM there are your mercs.
14- Army of Ultramar- Ultramarines with a bunch of IG allies or vice versa. Either way, the perfect way to show the most integrated defence force in the Galaxy.
15- Cadian Interior Guard- These are the guys that defend Cadia from the corruption from within that inevitable occurs in the eye. IG with SoB or GK forces, particularly inquisitorial forces, is the best way to represent this crack Witch Hunting force.
As you can see there is ALOT of potential to exploit the allies matrix to further explore the fluff of 40k on the table top. And that is just limiting yourself to the fluff of 40k. Imagine making a Halo army using Imperial Guard as UNSC marines and Space Marines for spartans with some landspeeder tornados (converted on wheels) for warthogs or bikes as mongooses (mongoosi?). Or maybe you feel taking a wack at the convenant, using Orks for brutes and gretchin as grunts and then taking some form of space marine or eldar as Elites. Maybe you want a Star Wars clone army, using IG with eldar allied psykers to be Jedi. Maybe you want to birth something from your own imagination. It is all up to you as the player, and allies can be a great medium to work in. But please avoid awful fluff