If you don't know much about Hash, this post will be a good starting point to pretty much learn everything about Hash (The first main part will be common hashes, the second main part will be Terpene Enhanced Hashes). First, I will point out that I do not use the word "Concentrates", just like "Cannabis" is an English Word, and "Marijuana" is a Spanish word, and they both mean the same thing. The same is basically true of the English word "Concentrates", the Arabic word "Hashish" and the Sanskrit word "Charas". Now, here are a list of Hashes/Charas, that are common:
THE MORE COMMON FORMS OF HASH:
Bubble Hash (Can be made in different grades)
Rosin (Can be made with a hair straightener)
BHO (Butane Honey/Hash Oil, made with Butane blasted through a tube full of Marijuana. There is also a safer produced form of BHO made with CO2)
Solvent Hash or RSO (RSO is Rick Simpson Oil, made with Naphtha and a Rice Cooker; Solvent Hash generally can be made with various solvents, such as Acetone, Alcohol, Hexene, etc. and can be left to dry or dried out another way. The basic concept is like making tea, and then getting rid of the liquid.)
Polarized Solvent Hash (PSH, is when you take 2 Solvents with different Polarity. For example, most things dissolve in Water, while Marijuana does not. This is why it is hard for Marijuana to be used in Hospitals, as it can not be injected, and will not diffuse in the bloodstream. It will dissolve in Milk, or Butter, or Oil. And Oil and Water do not Mix, they have opposing Polarity. So you get 2 Solvents with opposing polarity, and remove the THC from the Resins. A separatory funnel can be used to make the last part easier)
Scissor Hash or Hand Hash (Made with the material that collects on Scissors or your Hands when harvesting buds; to make it with your hands just get them covered and then rub your hands together and form it into a ball)
Butter (Not Hash, but an Extraction; Put Marijuana in Butter or Oil and heat it up, but not hot enough to Vaporize the THC; then use a Coffee filter or something to separate the solids, and put the butter or Oil in the fridge. You can also do this with Milk)
Distillate (Distillate is made with a Still, the same way as getting Alcohol from water; This is how "Reagent Grade" plant extracts are made)
Reflux (A more difficult, form of Solvent extract that allows you to use less solvent; as well as do things like Isomerization at the end. Isomerization could probably also be done with Distillate)
TERPENE ENHANCED HASHES (Newer Hashes)
The first and best example of Terpene Enhanced Hash is LHO. Similar to BHO, but instead of Butane Hash/Honey Oil, it is Limonene Hash/Honey Oil. The Limonene does not completely evaporate like the Butane (mostly) does, it stays in the Hash. And it is not a Contaminate, but a benefit. It makes the hash better, and has won a Cannabis Cup. You still Vacuum Purge it like Butane Hash to get all the Contaminates out, but the Limonene stays.
Live Resin. Live Resin is BHO made from fresh buds instead of Cured buds, so they have all their Fresh Terpenes, not evaporated by the Curing process (Curing basically = letting it dry out right). And the buds are kept in a Freezer until they are used. This creates Hash with more Terpenes in it than normal.
Sauce or Terpene Juice. This is almost the same as LHO, but instead of making the extraction with the Terpene, you just add the Terpene to the Hash afterwards, and it is done with many Terpenes, not just Limonene. The thing that makes Sativa different from Indica is the Terpenes, they both contain THC as their main active ingredient, but the Terpenes add the other effects.
Lastly, no one is really doing this at all as far as I know, but I have made BHO before with added Lemongrass. So I added Lemongrass with Marijuana to the Tube, then blasted the BHO through. Theoretically, this means that the BHO contained not only THC, but also Myrcene and Limonene (which are also in Marijuana). And the Hash was stronger, and acted faster, than normal Hash according to multiple people. There has been research on the effects of Myrcene and Limonene on THC, but no one is really taking other plants and mixing them. Other examples of plants with the same Terpenes as Marijuana include Pine (Pinol), Rosemary (Pinol), Lavender (Linalol), Uziza (Caryophyllene, which actually acts on the CB2 receptor and causes munchies, and is the actual molecule that Police dogs use to Identify Marijuana). So you could add these plants to a BHO tube, or an LHO extraction, or a Butter extraction, and your Hashes/Extractions will have different effects and flavors and smells than other people's.