What's the best topsoil?

Could you please elaborate on the factors that determine the best topsoil for gardening or agriculture? Are there specific nutrients, texture, or pH levels that are essential for optimal plant growth? Additionally, how do different types of soil, such as clay, loam, or sandy, compare in terms of their suitability for various plants and crops? Lastly, are there any environmentally friendly practices or amendments that can be used to improve the quality of soil naturally?