There are 3 classes of injectable diabetes medications.
GLP-1 Receptor Agonists
E.g. Exenatide (Byetta), Liraglutide (Victoza), Dulaglutide (Trulicity).
Amylin Analogue
Pramlintide (Symlin).
Insulins
Rapid-acting insulin, regular insulin, long-acting insulin.