Unofficial flags are either (a) flag

Flag

A flag is a piece of fabric with a distinctive design that is usually rectangular and used as a symbol, as a signaling device, or decoration. The term flag is also used to refer to the graphic design employed by a flag, or to its depiction in another medium.The first flags were used to assist...

s in regular use that have no official status or (b) flag concepts that have appeared in various publications.

Examples of the former type are: Boxing Kangaroo

Kangaroo

A kangaroo is a marsupial from the family Macropodidae . In common use the term is used to describe the largest species from this family, especially those of the genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern Grey Kangaroo and Western Grey Kangaroo. Kangaroos are endemic to the country...

, Fighting Kiwi

Kiwi

Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

, Chatham Islands

Chatham Islands

The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...

, Rotuma

Rotuma

Rotuma is a Fijian dependency, consisting of Rotuma Island and nearby islets. The island group is home to a small but unique indigenous ethnic group which constitutes a recognizable minority within the population of Fiji, known as "Rotumans"...

, West Irian, Jolly Roger

Jolly Roger

The Jolly Roger is any of various flags flown to identify a ship's crew as pirates. The flag most commonly identified as the Jolly Roger today is the skull and crossbones, a flag consisting of a human skull above two long bones set in an x-mark arrangement on a black field. This design was used by...

. These are examples of flags used at sporting fixtures, reproductions of no-longer-used historical flags, or used by a regional populace out of spontaneity, though not officially approved (or gazetted).

Examples of the latter type are: North Island

North Island

The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...

, South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

, Stewart Island/Rakiura

Stewart Island/Rakiura

Stewart Island/Rakiura is the third-largest island of New Zealand. It lies south of the South Island, across Foveaux Strait. Its permanent population is slightly over 400 people, most of whom live in the settlement of Oban.- History and naming :...

, 51-Star United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Flag, Antarctica. These are examples of flag ideas put forward by vexillologists/flag designers

Vexillology

Vexillology is the scholarly study of flags. The word is a synthesis of the Latin word vexillum, meaning 'flag', and the Greek suffix -logy, meaning 'study'. The vexillum was a particular type of flag used by Roman legions during the classical era; its name is a diminutive form of the word velum...

that have been picked up by various publications (books, magazine articles, online reference sites, etc).