Alrighty just felt like adding to this way flooded section with my personal favorite type of drug, opiates.

basics: Do not snort compound opiates, whether acetaminophen or ibuprofen,etc there will be more filler and non-opiate than opiate blocking up the mucus membrane and not allowing much if any of the goods to be absorbed. Also snorting acetaminophen tends to cause a burning sensation in your nose and if you continue doing it bleeding. so just don't snort compound opiates.
When taking compound opiates be sure not to go over 4grams of acetaminophen as that is the daily recommended limit and dosages higher than that can result in liver damage, also high doses of ace will increase feeling of nausea and make the high short lived due to feeling ill. If your tolerance is high enough that u much exceed 4grams of ace or you just want less in your body a Cold Water Extraction (CWE) is the best route to take aside from plugging.
Before I list common opiates/opioids I would like to say one thing DO NOT INJECT PILLS in my opinion it is not worth packing filler into your veins.
{Common Opiates}
Compound opiates:
Brand name- Opiate/other ingredient
Percocet/Tylex- Oxycodone/acetaminophen
Percodan/Endodan-Oxycodone/aspirin
Vicodin/Lorcet/Norco/Lortab-Hydrocodone/acetaminophen
Tylenol#1,2,3,4-Codeine/acetaminophen
Robotussin A-C/Cheracol-Codeine/guaifenesin
*Phenergan W/Codeine-Codeine/Promethazine
*Hycodan-Hydrocodone/homatropine
*Tusso-DF-Hydrocodone/guaifenesin

*syrup form

Non-Compounded Opiates:
Oxycontin/Roxicodone/Percolone/Oxyfast-Oxycodone
Dilaudid-Hydromorphone
Opana/Numorphan-Oxymorphone
Duragesic/Fentora/Actiq-Fentanyl

Other Opiate/Opioids:
*shitty shit that feels like shit.... shit!
*Ultram- Tramadol
Heroin- Diacetylmorphine
Opium- various extracted alkaloids

I'll leave this as is for now and i realize i left out propoxyphene which is because it's useless unless using to potentiate other opiates and contains high amounts of acetaminophen.
Feel free to contribute anything appropriate.

Great guide, I have suggestions though

shoot away by all means

fuck endocet, that shit made me soo sick. Never doing compounded oxy again in my life