Tallarn Desert Raiders
"Only two kinds of creature get fun in the desert: Bedouins and gods, and you're neither. Take it from me, for ordinary men, it's a burning, fiery furnace."
- – Mr. Dryden, Lawrence of Arabia
The Tallarn Desert Raiders are an Imperial Guard regiment in Warhammer 40,000. They're known for their love of mechanized warfare and guerrilla tactics. They come directly from 1988 POV, whereas the mujahideen are the good ones and the soviet the bad ones (take for reference the ending of
RAMBO III SLY MARBO III where the film was dedicated to the “brave Emprahideen fighters of Tallarn”.
They come from Tallarn, an Imperial planet that's pretty much entirely desert. It wasn't always; it used to be a lush, verdant, heavily-forested planet that was considered quite beautiful. But then the Iron Warriors tried to PULL AN EXTERMINATUS during the Horus Heresy. Luckily this failed as there were survivors hiding underground, leading to the Battle for Tallarn, the largest tank battle in the history of the Imperium of Man. Which they won, making Perturabo incredibly salty about losing to an army of mostly normal humans at mechanised warfare. Fuck, Perturabo was so determined to die on this hill that Horus himself told him to suck it up, fuck off and haul ass back to Horus' fleet before he pissed away the Iron Warriors legion in a fight he couldn't win.
They combine elements of Lawrence of Arabia, the Desert Rats of WW2, Erwin Rommel, and the various cultures of the Middle East. Thus, they are Awesome. Slightly less awesome (or more, if you're looking for a reprieve from all the Grimdark) is their close friendship with the Eldar, which they inexplicably get away with, including maintaining xenos artifacts on their homeworld.
The Tallarn did the Dorfs proud by digging too deep, and finding something black and shiny. As it turns out, this shiny thing was wanted by the Iron Warriors, as it was a Chaos relic that would let them accessorize. The Eldar then appeared (specifically those of the Biel-Tan craftworld), and after a few months of fighting they decided to ally against their common enemy. And so, holding the hands of the lesser Mon-Keighs and pinching their asses, they cleansed the world together with the power of friendship. They "exchanged rare promises of friendship", before the Tallarn did the only responsible thing they could with the artifact - cake it in rockcrete and forget about it (well, they did add some sealing rune stones from the Eldar, too).
During one particular campaign, the Tallarns ended up on the wrong end of a Munitorum fuck-up, leaving both their artillery and their tanks without fuel. In response, they dismounted their vehicles, walked the several dozen kilometres to their targets, and massacred them in an enormous cross-fire. The commander was so impressed, the 3 regiments were combined into the 1st Tallarn raiding regiment, and their vehicles given away to other regiments in need of mechanised support...which is like, a compliment while also giving them the short end of the stick.
The old metal models are far too expensive, and unvaried, for the average gamer to make an entire army out of them. Newer official art of the Raiders make them almost look like normal Guardsmen but with cloth wrapped around their heads - which PuppetsWar and Max Mini offer with their Desert Troopers Heads and Desert Dweller Heads respectively. Mad Robot Miniatures not only sells Shemagh Heads and Desert Veteran Heads, but Desert Torsos as well. Victoria miniatures has a complete sculpt available, but it’s a bit expensive. Forge World used to sell them, but not anymore. To play them on the table top your going to have to buy two whole squads of Veterans and some Plasma guns. Both expensive in real money and points. But if you’re playing IG you're used to getting screwed over in both IRL and the fluff, like always. Gripping Beasts "Arabian Spearmen and Archers" combined with Wargame Atlantics "Les Grognards" could give you some good looking cheap lookalikes. Another solid option is the Frostgrave Crewmen from North Star Military Figures, especially when combined with Cadian bits.
You know a IG regiment is badass when they outsmart the badasses of the Severan Dominate.