So, now that Only War is out, I figured a thread showcasing the regiments everyone is creating might be a good idea. I'll start us off with a Line Infantry regiment, because you can't get more IG than that!
103rd Patrochan Heavy Infanty 'The Black Collars'
The world of Patroch is home to a population of serious, dedicated workers who value good craftsmanship and industrious production little less than the Adeptus Mechanicus. Though all Patrochan goods are of excellent make, they are best known for a unique pattern of carapace breastplate, built with a reinforced gorget and alloyed with certain dense ores that found on few other worlds. All regiments tithed from Patroch find their soldiers outfitted with these fine cuirasses, and the time of a tithing sees a great frenzy of production as the necessary armor is produced.
The title of the 103rd Heavy Infantry comes from a notorious incident in the regiment's original founding, when a fault in the smelting process stained the gorgets across entire line of breastplates an inky black. The regiment was called to service before the armor could be reproduced, and prosecuted their campaign with an exemplary record and remarkably few casualties. Over the many centuries since this first incident, the 103rd has been re-founded as necessary, and with each Founding, their armor has the gorgets dyed black in honor of the armor that served so well in times past.

Characters belonging to the 103rd Patrochan Heavy Infantry gain the following advantages:
Characteristic Modifiers: +3 Strength, +3 Willpower.
Starting Aptitudes: Willpower.
Starting Skills: Athletics, Common Lore (Imperial Creed), Common Lore (Imperial Guard), Common Lore (Imperium), Common Lore (War), Linguistics (Low Gothic).
Starting Talents: Hatred (Mutants), Rapid Reload.
Blessed Ignorance: Characters from the Patrochan Black Collars are disinclined to seek knowledge proscribed by the common wisdom of their world, and suffer -5 to Forbidden Lore Tests.
Wounds: Characters from this regiment generate starting Wounds normally.
Standard Regimental Kit (Arms and Armor): Per player character—M36 Lasgun and four charge packs (Main Weapon), Imperial Guard flak armor, Good-craftsmanship Carapace Chestplate, knife, two frag grenades, two krak grenades.
Standard Regimental Kit (Tools): Per player character—Microbead. Per Squad—Auspex.
Standard Regimental Kit (Miscellanea): Per player character—Chrono, Uniform, Poor weather gear, sling bag, basic tools, mess kit, water canteen, blanket, sleep bag, rechargeable lamp pack, grooming kit, cognomen tags, Imperial Infantryman's Uplifting Primer, two weeks of combat sustenance rations.
Favored Weapons: Grenade Launcher (Special), Autocannon (Heavy)

Creating the Patrochan Black Collars
Home World: Imperial World
Commanding Officer: Phlegmatic
Regiment Type: Line Infantry
Doctrines: Iron Discipline
Total Cost: 7 points (+10 points towards Standard Kit)
Additions to Standard Kit: Good-craftsmanship Carapace Chestplate (15 pts, +5 pts for craftsmanship), Microbead (8 pts), Chrono (2 pts), Auspex (10 pts, one per Squad)
Further Notes: This is a regiment designed to keep the players alive and intact a little more than usual. The extra armor and the Willpower aptitude should help with both physical and mental hardiness, while the rest of the equipment reflects their planet's inclination towards doing things thoroughly, including outfitting their regiments. Good, solid, dependable equipment--plus, the Auspex makes technical characters like an Operator useful even when the Squad has no vehicle assigned to them. The weapons were chosen for being able to engage light vehicles and heavier infantry, the sorts of opponents a Squad might have difficulty with but still be expected to overcome. They also are powerful without risking being overly strong in the hands of a starting Weapons Specialist or Heavy Gunner.