Frogs And Toads On Stamps, Covers And Postmarks.

Czech Republic
Definitive Issue
September 7, 2016
Tree frog (Hyla arborea)
(graphic design: Libuše and Jaromír Knotek)

Austria
Fauna self-adhesive
February 25, 2008
Common Tree Frog (Hyla arborea)

Costa Rica
Flora and Fauna
December 16, 1986
partial set of two:
Hourglass Treefrog (Dendropsophus ebraccatus)
Lovely Poison Frog (Phyllobates lugubris)

I love frogs for sure, here is some from my collection:

Absolutely lovely Yellow-bellied Toad from Liechtenstein, year 2014 (Look at those eyes):


It's yellow-bellied Toad again! From Switzerland again, year 1997:


Agile Frog from Jersey, year 1989:


Natterjack Toad from UK of Great Britain and Northern Ireland, year 1986:


Crane Frog from Hungary, year 2003:


Common Tree Frog from Hungary, year 2003:


Seoul Frog, Moor Frog and Common Toad. From North Korea, year 1992:
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Black-spotted frog, Oriental Fire-bellied Toad, American Bullfrog and Common Toad. From North Korea, year 1974:


I have some more frogs, but they are already posted here by others.

Botswana
Frogs
March 23, 1992
Boettger's Metal Frog (Cacosternum boettgeri)
Painted Reed Frog (Hyperolius marmoratus angolensis)
Fenoulhet's Toad (Bufo fenoulheti)
African Reed Frog (Hyperolius sp.)

Zambia
Frogs and Toads
January 25, 1989
African Red Toad (Bufo carens)
Natal Dwarf Puddle Frog (Phrynobatrachus natalensis)
Marbled Reed Frog (Hyperolius marmoratus)
Marbled Reed Frog (Hyperolius marmoratus) juvenile

Zimbabwe
Frogs
December 9, 2014
Swynnerton's Reed Frog (Hyperolius swynnertoni)
Giant Bullfrog (Pyxicephalus adspersus)
Bushveld Rain Frog (Breviceps adspersus)
Inyanga River Frog (Amietia inyangae)

Ecuador
Amphibians - Frogs
March 31, 2016
Booklet of 8 self-adhesive stamps (imperforated)
Anthony's Poison Arrow Frog (Epipedobates anthonyi)
Prince Charles Stream Tree Frog (Hyloscirtus princecharlesi)
Little Devil Poison Frog (Oophaga sylvatica)
Ecuadorian Horned Frog (Ceratophrys stolzmanni)
Andean Marsupial Tree Frog (Gastrotheca riobambae)
Glass Frog (Hyalinobatrachium aureoguttatum)
Imbabura Tree Frog (Hypsiboas picturatus)
Rio Pescado Stubfoot Toad (Atelopus balios)

Bahamas
Fauna
August 15, 1984
Set of four, one stamp shows Greenhouse Frog (Eleutherodactylus planirostris)

Suriname
Frogs and Toads
June 24, 1981
Tiger leg monkey frog (Phyllomedusa hypochondrialis)
Smoky jungle frog (Leptodactylus pentadactylus)
Rusty tree frog (Hyla boans)
Common walking leaf frog (Phyllomedusa burmeisteri)
Dyeing dart frog (Dendrobates tinctorius)
Smooth-sided toad (Bufo guttatus)

Swamps and other wetlands are the home of specialized and endangered creatures such as the Cranwell Horned Frog (Ceratophrys cranwelli). If swamps are drained it not only threatens the survival of countless species, but also makes flooding more likely because wetlands and swamps can absorb great amounts of rain.

South Africa
Cape Floral Protected Region
September 23, 2011
Set of ten, one stamp shows a Cape Ghost Frog (Heleophryne purcelli).

Australia
Stamp Collecting Month - Endangered Wildlife
September 20, 2016
Set of seven, one stamp depicts Southern Corroboree Frog (Pseudophryne corroboree) native to Southern Tablelands of Australia.

Ecuador
Tourism - All You Need is Ecuador
November 13, 2015
Set of 16, one stamp features Ecuadorian Horned Frog (Ceratophrys stolzmanni).

Bosnia and Herzegovina (Serbia)
European Protection of Nature - Amphibians
September 12, 2013
Set of two, one stamp depicts Agile Frog (Rana dalmatina).