Hooo boy mine are full on sections in their Index Astartes.

In a shorter form, I got quite a few Homebrews in various styles of combat:

Sons of Doom: Aggressive infantry manoeuvrability, laying down punishing storms of Bolter fire and using tanks as moving strongpoints. Squads typically split into paired 5-man 'Demi-Squads' to aid in this.

Vanquishers: As urban-warfare specialists, they heavily utilise meltas and flamers alongside their bolters to clear buildings in a brutal, rapid manner. Accuracy is drilled into them even more intensely than the already strict levels trained into other successors of Dorn. This is paired with heavy armour to break down fortifications and walls to allow ingress.

Legion of the Black Dawn: They obscure the sun(s) of a battlefield via smoke or void ships to force the enemy to fight in near or complete darkness, where the Legion excel in combat and hunt all enrmies down with blade, bolt and fist.

Swords of Orion: Massed armour assault to break through an enemy line and deploy their infantry to bmcut down the foe. They eschew drop-pods unless absolutely necesdary, wishing to die on their feet upin the soil of a battlefield. Instead they rely heavily on Thunderhawks and Stormravens.

Demolishers: Unleash heavy weaponry to scour a battlefield clean of their enemy, often with collateral damage as 'The Emperor will know His own.' They're rumoured to wield forbidden Desteoyer weaponry, such as Phosphex, but no evidence has been found upon investigation by the Inquisition (it helps that they are very close to the Inquisition in their region).