Staining is a major part of histopathology, as it's used for diagnosis of disease and for identifying different cells/cell types. The most used stains in the lab are H&E, AB/PAS and Papanicolaou. These stains are made of a series of some of the following stains!
Eosin - Stains proteins in the cytoplasm, collagen and muscle fibres. Shows the cytoplasm stained pink-orange and nuclei stained blue/purple. Eosin also stains red blood cells red
Haematoxylin - Stains cell nuclei blue
OG-6 - Stains the cytoplasm or keratin
Alcian Blue - Used to stain acidic polysaccharides such as glycosaminoglycans in cartilages and some types of mucopolysaccharides
EA-50 - Provides colour contrast in Pap staining for nucleoli, squamous cells, cilia, and erythrocytes
These are just the routine stains used in the lab, plenty more special stains are used for more complex applications! 👩🔬