Water is a great solvent. It’s neutral and doesn’t provide any strong positive or negative effects. It just helps components to mix better and to transport active components.
PEG-40 Hydrogenated Castor Oil helps ingredients to mix better. It has nice cleansing activity helping to remove sebum and dirt from the surface of your skin. It's also responsible for making soft foam in soaps, shower gels, etc. Despite it having "PEG" in the title, it's considered to be safe.
Propanediol is a good solvent, emollient and humectant. It helps to moisturize the skin and prevent moisture loss. In haircare products, it conditions hair and improves absorption of the product.
Pentylene Glycol is a great replacement for Propylene Glycol. It has very similar characteristics but it’s derived from plants (usually from corn). Natural cosmetics lovers will find this component very useful. It enhances the moisturizing effect of cosmetic products, improves the efficiency of preservatives and it’s an effective emulsifier. It’s approved by ECOCERT and COSMOS so it’s considered to be 100% safe and can be used in vegan products.
Polysorbate 20 doesn’t have any notable skin benefits but is used in cosmetics quite often. Manufacturers use it for formulation purposes. It improves the scent, texture, and feel of the product.