1. Orcs, Grey or Green. Grey Orcs live in colder climates up north, or mountainous highlands. Green in forests and verdant hills. Grey warriors wear mail and wield steel weapons, while green are primitive but skilled in poisons and witchery. These are middle-road fantasy orcs: tusks, muscles and bristly manes; can be hot in a beastman kinda way or butt-ugly pig people. Greys are nobly savage while greens are savagely noble. They can get along with humans alright but old enemies to dwarves and elves. More an alt. PC race than an enemy.
2. Orcs, White. Driven deep underground long ago. Have abandoned their old gods for Demon Princes, partic. Baphomet, Demogorgon, Kotschie, or Obox-Ob. Followers of rival princes fight each other as often as anyone else. Champions and chiefs always sport at least one demonic "gift" (significant mutation---six arms, ceratinous armor, acid tongue, etc). Metalworkers, masters of crafting Arcane Tattoos.
3. Orcs, Pink. Creations of the Arch-Wizardess Cyrell the Chaotic. Their genetic matrix is highly unstable: virtually all have at least a minor mutation (us. extra eyes or teeth ridges over limbs etc.), 50% have major mutation. Flesh rubbery and soft. Explode when slain, which gives them unwarranted confidence. Cyrelle grants her followers stylish black leather armor and fine weapons; feral examples will fight with what they can scavenge.
4. Orcs, Ochre. These Orcs' liverspotted yellow flesh is overgrown with pustules, many as big as a fist. When popped these spheres release acid (if damaged, d3 splash 5 ft). Some also vomit acid (d6, 5ft). Many orcs become so swollen with pustules they cannot wear armor and live in constant pain. Primitive, us. fight with greatclubs or stone axes. Those who become champions often wear Otyugh or Troll-hide amor, which resists acid spills better. They grow in gigantic, dangling batches of birthing cysts like grape bushels. Probably a wizard created them but none willing to take credit.
5. Orcs, Violet. Symbiotic relationship with large gilled shelf-fungus called Dream Polypore, brackets of which grow mainly off shoulders and back, staining skin purple. Fungus constantly emits trickles of smoke-like purple sporeclouds, which Violet Orcs can manipulate to show minor illusions or exhale hallucinogenic exhaust once per day. Have their own language based on thought-forms half-glimpsed in the haze. Makes hiding tough for them. Dreamy, peaceful, they see a heightened version of reality. If encountered may trade potions or other herbal magic items. Maybe a good PC option, but wearing armor problematic---only decent as Druid or Sorcerer.
6. Orcs, Red. Base 2HD. Vomit a shower of their own blood, which is as flammable as gasoline. Their skins are resistant to flame. Usually well-equipped, they favor scale mail, the voulge-glaive and two-handed falchions. All Red Orcs descend from a batch created by a wizard centuries ago and consider themselves to be a single nation: they will fight for anyone's pay, but not each other. Beneath their disciplined facade each is capable of entering a truly terrifying but always fatal rage, gaining +4 Str/+10' Spd and taking 1d4 dmg/rnd from their own boiling blood until, steaming, it squirts from eyes and nostrils and they collapse dead.
7. Ogrillons. Also known as "Orcres" thanks to my players. The product of an Orc and Ogre mating. Most are Med. size (< 8 ft) but a few (10%) reach Lg. size. A degree of ogrish natural armor, and powerful natural weapons including thick bonespurs protecting/reinforcing fists and tusks able to gore. Suffer from the ogres' Hunger Curse only slightly less. Most orc tribes regard them as abominations but a few use as shock troops. Sometimes hags breed them as they eat slightly less than Ogres so you can keep a few more around.