After reading many ingredient lists of popular shampoo bars, I selected these common ingredients. Because in addition to wanting to make a natural soap product, I wanted one that does a good job even if I had to use something not organic. I also wanted ingredients that were created without solvent residues like Sodium lauryl sulfate that seems to be the main ingredient in the most commercial bar shampoos. So below is an explanation of ingredients I have settled on for now

Ingredients:
Sodium Cocyl Isethionate, Organic Creamed
Coconut Butter, Sodium Coco Sulfate, Decyl
Glucoside, Stearic Acid, Behentrimonium
Methosulfate and Cetearyl Alcohol, Organic
Aloe Vera Oil, Tea Tree & Sage Essential Oils,
Pantothenic Acid (vitamin B5), Ascorbic Acid
(vitamin C), Titanium Dioxide for color

Sodium Cocoyl Isethionate exhibits high foaming ability, producing a stable, rich and velvety lather that does not dehydrate the skin, making it ideal for addition to water-free products as well as skin care, hair care, and bath products. This high-performance surfactant, which is equally effective in both hard and soft water, is a popular choice for addition to liquid shampoos and bar shampoos, liquid soaps and bar soaps, bath butters and bath bombs, and to shower gels, to name a few foaming products. This lightly-scented and conditioning cleansing agent is gentle enough for use on the delicate skin of babies, making it an ideal surfactant for makeup as well as personal care products and natural toiletries. Its emulsifying property, which allows water and oil to mix, makes it a popular ingredient in soaps and shampoos, as it encourages dirt to attach itself to them, which in turn makes it easier for it to be washed away. Its deluxe foaming capacity and conditioning effects leave the hair and skin feeling hydrated, soft, and silky-smooth.

CREAMED COCONUT,
also known as coconut butter, is a coconut product made from the unsweetened dehydrated fresh pulp of a mature coconut, ground to a semi-solid white creamy paste. It is sold in the form of a hard white block which can be stored at room temperature. Contains both the natural pulp and oil of the coconut, Easily absorbed by the skin and hair leaving it soft and nurtured with the natural protein, potassium, magnesium and iron...

All natural plant derived Decyl Glucoside is a premium non ionic surfactant derived from natural and renewable feedstock. It is used for formulating many quality products like liquid soaps, shampoos , body washes, and high quality institutional cleansers.
Decyl Glucoside is a fatty polyglycoside prepared by reacting cornstarch glucose with Natural fatty alcohol.
Decyl Glucoside is highly recommended for use in shampoos, shower gels, bubble baths, hand and face cleansers, and other applications where mildness and cleansing performance are required. It contains no solvents or hydrotropes and is easily formulated in personal care products. Being nonionic, Decyl Glucoside is compatible with cationic surfactants and polymers, and is recommended for conditioning shampoo formulations. Due to its natural chemistry, decyl glucoside is very mild and low in toxicity.
Decyl Glucoside Advantages:
_ Made from 100% natural, renewable, plant-derived feedstocks
_ Readily biodegradable
_ Excellent foaming capacity and cleansing properties
_ Stable even in low pH applications
_ Gentle and effective - proven mildness
_ Free of sulfates, preservatives, and EO
_ Compatible with various surfactants
_ Flexible and multi-functional

Sodium Coco Sulfate is a surfactant. All surfactants are partly water-soluble and partly oil-soluble, allowing oil and water to become dispersed. Above a minimum concentration, the surfactant molecules become organized in a structure that can trap the oil-based dirt from the hair, allowing it to be rinsed away.

Want to know the difference between SLS & SCS? Read on...

There is a lot of confusing information going around the internet about the similarities/differences between Sodium lauryl sulfate (SLS) and Sodium coco sulfate (SCS) in particular.
There are lots of different surfactants (detergents & foaming agents) used in cosmetic and household products, many of which have names that sound similar to SLS but are very different in terms of their irritancy to the skin. These can be made in similar ways and have similar names but they vary massively in terms of how harsh they are to the skin. Sodium Coco Sulfate, SLES, Ammonium Lauryl Sulphate (ALS), Sodium Myreth Sulphate, and Sodium Lauryl Sulfoacetate to name but a few.
If we specifically look at SLS (sodium lauryl sulfate) versus SCS (sodium coco sulfate); both ingredients are made in the same way, by treating fatty acids with sulphuric acid and then neutralizing with an alkali. The difference between them is that SLS is made using purified and isolated Lauric acid, whereas SCS is made using whole Coconut oil.
The result of using these different starting materials is that SLS is a relatively simple molecule and has a small molecular mass enabling it to easily penetrate the outer layers of the skin and cause irritation to underlying living skin cells. On the other hand SCS has a more complex molecular structure which has a much greater molecular mass. This prevents it from penetrating the epidermis, and means that it has far less irritancy, as it cannot reach the living cells under the skin surface.
This difference is recognized by international authorities, and in fact these two molecules do have different CAS Numbers (Chemical Abstracts Service which identifies all chemical compounds in an internationally approved database). The CAS Number for SLS is 151-21-3, but for SCS it is 97375-27-4. This can be confirmed by checking the official EU Cosmetic Ingredient Name (CosIng) website.
Sodium Coco Sulfate is permitted by the OFF & Soil Association who certify Green People & Skin Blossom products, some of the brands that use sodium coco sulphate.

Stearic Acid
A vegetable derivative used to stiffen and stabilize lotions and cremes. Occurs naturally in vegetable fats. A white, waxy, natural fatty acid.

Behentrimonium Methosulfate (and) Cetearyl Alcohol
An excellent emulsifier, BTMS is key when looking to create amazing hair care conditioning products, which is why it is often referred to as the "Conditioning Emulsifier" Derived from the Colza plant(Rapeseed), BTMS is a unique emulsifier in that it is a cationic (carrying a positive charge) quaternary compound, while most other emulsifiers are non-ionic (carrying a neutral charge). This means that the positively charged BTMS is attracted to the negatively charged hair strands (or neutral skin), and will absorb and cling on to the surface, resisting being easily rinsed off, which gives the feel of long lasting hydration and conditioning (great for leave-in conditioners, water resistant lotions), plus boosts lubricity and static control, which helps reduce friction and pull during wet comb-outs and brushing.

Gentle and effective, BTMS helps hair retain a springy bounce and volume, while leaving it feeling silky smooth. It is also very effective for use in skin and body care products, especially when a light, powdery soft, non-greasy feel and finish is desired. BTMS is free from ethoxylated ingredients.

Organic Aloe Vera Oil
Cold pressed to preserve quality (But heated during making the shampoo bar) Aloe vera oil is an excellent choice for many of the same things as aloe vera gel and juice, but it has a different texture which makes it more comfortable on the skin and more soothing internally. Adding some of this potent ingredient to shampoo can make your hair silkier, smoother and more manageable while minimizing dandruff as well.

Pure Steamed Essential oils
Add scent in addition to the natural coconut scent of the creamed coconut butter.

Panthenol acts as a lubricant on the skin surface, which gives the skin a soft and smooth appearance. Panthenol and Pantothenic Acid also enhance the appearance and feel of hair, by increasing hair body, suppleness, or sheen, or by improving the texture of hair that has been damaged physically or by chemical treatment. Panthenol and Pantothenic Acid (vitamin B5) have the same biological activity and Panthenol can be converted (by oxidation) to vitamin B5 in the skin. Pantothenic Acid is found in all living cells and tissues and is essential for normal metabolism and hormone production.

Ascorbic Acid is commonly known as Vitamin C. Salts of Ascorbic Acid. These ingredients are used in a variety of cosmetics and personal care products including makeup, as well as skin and hair care products. Ascorbic Acid and its salts are used in the formulation of personal care products as antioxidants to slow deterioration caused by exposure to the air and also to control the ph of the finished product. Ascorbic Acid is an essential nutrient required for collagen production, tissue repair, and for the synthesis of neurotransmitters. It also acts as an antioxidant, plays a role in resistance to infections, and is used for the treatment and prevention of scurvy.

Titanium Dioxide is a naturally-occurring mineral found in the earth's crust.
Because of its white color, opaqueness, and ability to refract light, the ingredient is often used as a pigment, brightener, and opacifier, which is an ingredient that makes a formulation more opaque. Titanium dioxide is also a UV filter and so is an effective active ingredient in sunscreens. It's often used in cosmetic loose and pressed powders, especially "mineral powder" cosmetics, in addition to other cosmetics, lotions, toothpaste, and soap.