To add to
winona’s fabulous list, these are my notes on the various oils and additives that are in my personal arsenal:
Almond (high Vitamin E content; softens, strengthens & nourishes; treats hair loss, breakage & scalp issues; smoothes cuticle)
Amla (penetrates the scalp and strengthens the hair at its root; not only stops abnormal hair loss, but reverses its effects which promotes stronger, healthier new growth; excellent conditioning herb
Argan (contains Vitamin E and antioxidants; rich in unsaturated EFAs which serve to strengthen the protein bonding structures in hair thereby improving its strength and healing split ends; gives new life to dry, tangled and flyaway hair; has properties similar to those of Jojoba; hydrates and penetrates to enhance elasticity; nourishes and promotes growth; strengthens by repairing damaged cellular membranes caused by destructive agents; cures brittleness, restores smoothness and manageability, and increases the life of color-treated hair; enriches hair growth and pigmentation; prevents dandruff and the premature graying of hair; increases the strength of the hair follicles, which prevents hair-fall; brings forth a rich, natural shine and soft texture to the hair as well as helps rejuvenate hairs that are dull and damaged; it also prevents split hair ends)
Babassu (fast penetrating oil; one of nature’s richest emollients, beneficial for either dry or oily complexions; nourishes and restores hair’s strength, resulting in shiny, healthy-looking hair)
Black Cumin Seed (Containing a rich variety of vitamins including A, B1, B2, B6, C, Niacin and Folacin and an impressive array of minerals including calcium, potassium, iron, magnesium, selenium, copper, phosphorus and zinc; is known to be particularly effective at combating auto-immune skin disorders, making it a natural choice for psoriasis treatment; it can also help to soothe acne and various forms of eczema; may also help relieve pain caused by arthritis or sore muscles and is an excellent choice for massage oil blends)
Black Seed (high EFAs and amino acids; penetrative; improves circulation; is antiseptic, astringent, cleansing, & skin regenerative; helps prevent hair loss, stunted growth & thinning; strengthens, nourishes & conditions the hair and scalp)
Brahmi (outstanding hair nourisher due to its antioxidant properties that enables the production of healthy roots which promotes growth and thwarts hair loss and dandruff; it is the best therapy for people who have chronic hair problems; continued use results in long, dense, black and lustrous hair; prevents hair fall out and premature graying
Broccoli Seed (rich in Vitamin A, arachidonic acid & polyunsaturated acids; has a unique composition of fatty acids that are useful for imparting a sheen and luster that is comparable to silicones; its quick penetrating action that helps reduce the greasy after feel; quickens hydration of the skin; highly moisturizing)
Camellia Seed (moisturizes softens, and protects hair; provides hair with luster and shine; promotes hair growth)
Castor (germicidal, insecticidal and fungicidal properties that cleans the scalp of any impurities that inhibit maximum growth; humectant; moisturizes hair and scalp; prevents dryness; promotes growth & thickness; EFAs nourish & prevent scalp dryness by retaining moisture; increases softness & shine)
Extra Virgin Coconut aka EVCO (highly penetrative - it is the only natural oil that can penetrate all three layers of the hair shaft; rich in vitamin E, natural fortifying fatty acids and emollients that have an innate attraction to the proteins in hair, which allows for deeper penetration; it has been proven to enhance, moisturize and strengthen the hair shaft, and thereby reduce split ends, dryness and breakage; its affinity for protein results in a high degree of penetration, which causes it to resist protein reduction (reduce the amount of protein that is lost); it also replenishes vital oils as well as giving the hair shine, softness and bounce; is also known to have antifungal and antibacterial properties, therefore, it can be used for common scalp problems, to heal insect bites and pimples of the scalp, in addition to keeping lice away from the scalp; it promotes overall scalp health, which is crucial for the growth of healthy hair; it is especially ideal for dry hair, which is more prone to hair breakage and damage; has powerful antioxidant, antifungal, antimicrobial, and antibacterial properties; can be drying if used in excess)
Emu (natural DHT blocker; highly penetrative – is able to access all layers of the skin and hair, and is able to take other substances along with it for deeper penetration; has anti-inflammatory, antibacterial & antifungal properties; able to rejuvenate skin cells and wake up lifeless hair follicles to the anagen (growth) phase; fosters follicle development and growth by increasing the synthesis of DNA in the epidermis which results in the stimulation of skin regeneration and the proliferation of the cells around the hair follicle; thickens the hair by enlarging the follicles)
Flax Seed (a rich source of alpha-linolenic acid (ALA) and the Omega-3 series of essential fatty acids; topical use allows the body to absorb some of the essential fatty acids necessary for healthy cellular activity; can help soften and heal skin abrasions, reduce the swelling and redness of lesions due to skin disease and improve the health of the skin)
Fractionated Coconut (has an indefinite shelf life; a light, non-greasy, non-staining, liquid oil; is a good choice for use in massage, skin care and soap formulations because it is a useful carrier oil since it helps to carry therapeutic oils under the skin; unlike EVCO, it will retain its liquid form at lower temperatures)
Grape Seed (high EFA content; antioxidant properties; induces hair growth through the proliferation of hair follicle cells; prevents hair loss)
Hemp Seed (contains ceramides; penetrable; imparts gloss and manageability to hair; aids in keratin formation; helps to increase volume, comb ability and shine; smoothes down the cuticle of hair)
Jamaican Black Castor aka JBCO (unrefined, pure dark castor oil that contains a high ash content, which means it contains or Silica, Magnesium and other elements that serve to strengthen and thicken the hair, thereby making it more potent than the regular processed castor oil; serves to improve the condition of hair and skin; helps to keep the hair thicker, shinier, and less prone to damage or breakage; may be used for skin conditions, such as eczema, liver spots, moles, pimples, rashes and warts; it also helps improve the appearance of calluses by keeping them soft and supple; effective against muscle and joint pain)
Jojoba (moisturizes extra dry, thirsty hair; infuses moisture directly into the scalp; improves elasticity, moisture balance & lasting shine with consistent use)
Karanja (this cousin of Neem offers an array of similar therapeutic benefits; has insecticidal and antiseptic properties; can be used to treat eczema, psoriasis, skin ulcers, dandruff, or to promote wound healing; has a milder, nutty, it has a more versatile aroma than Neem Oil)
Kukui Nut (high Vitamin A, C, E and EFAs; penetrative; contains ceramides; creates a protective shield that locks in moisture; increases softness, shine and detangling ability)
Macadamia Nut (penetrative; easily absorbed by both the hair follicles and the scalp, resulting in less amounts of dandruff, increased silkiness and shine of the hair, and even a promotion in the rate at which the hair grows; emollient; properties are very similar to mink oil and sebum)
Neem (contains EFAs and Vitamin E; intensive hair and scalp treatment that repairs damaged hair and restores healthy sheen and manageability; stimulates circulation of the scalp and supports hair growth; discourages flaking and irritation of the scalp; a stimulant that promotes growth; an anti-bacterial, anti-viral, anti-fungal, antiseptic, and anti-parasitic agent used to treat skin disorders such as eczema, psoriasis, ringworm, scabies, syphilitic sores, gingivitis and chicken pox)
Palm (rich in oleic and palmitic acids, magnesium and Vitamins A, E & K ; a natural source of anti-oxidant; resists oxidation and rancidity, which means products made using palm oil have extended shelf lives)
Pumpkin Seed (contains high levels of iron, manganese, magnesium, zinc, phosphorus, copper, potassium, amino acids and Omega 3 & 6; natural DHT blocker; decreases hair loss)
Red Palm (softens, improves elasticity, and adds shine; has antibacterial properties which aids in providing a healthy growing environment for your scalp and hair follicles; does not lose its nutrients when it is heated; very heavy, thick oil that solidifies at room temperature)
Rice Bran (contains ceramides; adds sheen and manageability while moisturizing and conditioning hair; imparts shine and texture, leaving hair easy to style; contains proteins that help strengthen the hair shaft and prevent split ends)
Sesame (penetrative; softens, strengthens & nourishes; promotes hair growth; has hair darkening abilities)
Shikakai (has a naturally low pH, as well as conditioning and strengthening properties)
Sunflower (contains ceramides and Vitamins E & A; nourishes and protects for silky, strong, healthy hair; hair strengthener; prevents aging of the hair follicle, which may delay graying)
Walnut (rich in ceramides, Vitamins A & C and linoleic acid; conditioning hair oil that provides flowing, smooth and manageable hair)
Wheat Germ (rich in Vitamins A, D & E; contains ceramides and proteins)
, when oils are discussed, it is usually in regards to a regime therefore it's listed but not explained. 
I think that the veteran HHJ divas, primarily know what they are used for so there is no need for explanations.
Castor oil is heavy and will seal in moisture like nothing else. It's heavy so I only recommend using on the ends. Jojoba oil is light and not greasy. Jojoba is also great if your face gets dry in the winter. 
