mat-button  Rectangular text button w/ no elevation

mat-raised-button   Rectangular contained button w/ elevation

mat-flat-button     Rectangular contained button w/ no elevation

mat-stroked-button  Rectangular outlined button w/ no elevation

mat-icon-button     Circular button with a transparent background, meant to contain an icon

mat-fab     Circular button w/ elevation, defaults to theme's accent color

mat-mini-fab    Same as mat-fab but smaller