This is one of the five families that make up the order Pelecaniformes.

These are usually medium to large wading birds that are mainly found on coastal and inland waters.
There are approximately 66 different species within approximately 16 to 18 different genus. They are worldwide in their distribution (as a family), though some genus are found in only certain parts of the world.
Out of the approximately 66 different species, the following list are the ones that are commonly seen somewhere within the United States:
American Bittern
Least Bittern
Great Blue Heron
Great Egret
Snowy Egret
Little Blue Heron
Tricolored Heron
Reddish Egret
Cattle Egret
Green Heron
Black-crowned Night Heron
Yellow-crowned Night Heron
Other species are found throughout the rest of the world. Once it is safe to travel again, and if I manged to get picture of members of this family found outside the US, they will be added here (in addition to their own page).