Spherocyte

Spherocytes are found in all hemolytic anemias to some degree. Hereditary spherocytosis and autoimmune hemolytic anemia are characterized by having only spherocytes. Where spherocytes are very frequent autoimmune hemolysis or hereditary spherocytosis should be considered.

https://en.wikipedia.org/wiki/Spherocytosis

https://haematologyetc.co.uk/index.php?title=Spherocytes

Inherited defects of membrane proteins (hereditary spherocytosis)

Instability of the lipid bilayer (band 3 deficiency)
Reduced cytoskeletal density (defects of spectrin, ankyrin, or Band 4.2)

Immune damage to erythrocyte membrane (immune haemolytic anemias)

Autoimmune haemolytic anaemia: spherocytes are most obvious in warm autoimmune haemolysis, but may also be seen in cold haemagglutinins or drug-induced haemolysis
Alloimmune haemolysis including immediate and delayed transfusion reactions and haemolytic disease of the newborn.

Physical or chemical damage to the erythrocyte membrane (non-immune haemolytic anaemias)

Microangiopathic haemolytic anaemia
Physical e.g. mechanical valve
Toxins e.g.
Clostridium perfringens
Heat e.g. burns