Opioids like any other drug, have many slang names. I’m sure these are but a few.

I had to look them up 🙂

Heroin has been around a long time: Black tar, Smack, H, Dope, Junk, Horse, Skag, and Brown Sugar. 
Very pure heroin is commonly known as China White

Heroin is often mixed with other substances, creating specific slang combinations. For example, a mix of heroin and cocaine is known as a speedball, Belushi, or boy-girl.
While heroin mixed with crack cocaine is called chocolate rock or dragon rock. 

Some slang terms when referencing effects or usage of heroin are: dragon (derived from "chasing the dragon"), nod, or “chasing the dragon”.

Heroin combined with cold medicine is referred to as cheese, and heroin mixed with alprazolam is called bars.

Fentanyl: Apache, China Girl, China Town, TNT, Murder 8, Fetty, and Blues (referring to counterfeit pills resembling Percocet), poison, tango and cash.

Some others: Fenty or Fet, Goodfella, Dance Fever, Jackpot, King Ivory, He-Man.

Fentanyl mixed with xylazine: Trans Dope or Zombie Drug

Oxycodone (including OxyContin and Percocet) is frequently called Oxy, Percs, Roxy, Hillbilly Heroin, OC, 30s, or M30s. Blues, Blue M30s, Perc 30s, M30s.  Some of these refer to counterfeit Oxy pills containing  fentanyl.

Opium:  Big O, or ‘O’,  Hop (or Hops), Midnight Oil, Dope, Smack, Chasing the Dragon, Joy Plant, Aunti (referring to the pipe), and Black or Black Tar; black stuff, Chinese tobacco, chocolate, dopium, Dover’s Desk, dream gun, joy plant, zero, amongst other.

Hydrocodone (including Vicodin and Lortab) is often called Hydros, Norco, or Fluff. Vics, Vicos, Vikes, Hydros, Norco, Watsons, 357s or Watson-387, Tabs, and Fluff.

Hydromorphone (Dilaudid): Hydro, Dillies, D, Football, or Juice, Smack, hospital heroin.

Codeine (often in syrup form known as Lean, Sizzurp, or Purple Drank, Captain Cody, Cody, or Schoolboy. Texas tea, dirty sprite, barre, toss, Texas mud, Tsikuni.

Doors and Fours: Codeine combined with glutethimide.

Morphine is referred to as M, Miss Emma, Monkey, White Stuff, or God’s Drug; Mister Blue, Morpho, Dreamer, God’s Drug, Monkey, Unkie, Vitamin M, Salt and Sugar, and White Lady.

Methadone is commonly called Amidone, Dollies, Fizzies, Mud, or Red Rock; Tootsie Roll. Meth, Phy, Junk, Metho, Jungle Juice, Chocolate Chip Cookies, Maria, Pastora, Wafer, and Juice.  And sometimes linctus.

Oxymorphone (Opana): Mrs.  O, O Bomb, Octagons, Stop Signs, Blue Heaven, Biscuits, Pink Lady, Blues, Pancakes, and Pandas.  Octagons, Pink, Pink Heaven, or Pink O

Tramadol: chill pills, trams, trammies, ultras, and tramal.