Here’s a wiki of online shops where to get postcards, organized by country where they are based. Feel free to edit it to add your favorite shops to it too — just click the button underneath this post!
Argentina
Australia
Australia Postcards
Australia Post
Australiana Souvenirs
Doodads- 3D postcards
Fishpond
Mitch Revs
Natalie Parker Prints
The Curatoreum
Utopia Homewares
zetta florence
Etsy Shops
ClosetPlannerAddict
EnjoyIllustration
goldstpress
GreenMiniCreative
JocelynProustDesigns
MonicaMcnabDesigns
Belarus
Belgium
Bol.com for postcard boxes
Cato Oyen
Dille en Kamille
Flore Deman
Hello August
Inne Goossens
Jollyfish
Kaart Blanche
Liefde in tijden van corona
The Other Shop
Papierpret
La Photo Postale
Plaizier
SOMAJ
Withloov
Bodesigns
Sanne Verstraelen
Studio Bertha
Brazil
Colab55
Danieli Dagnoni
Garage Atelier de Arte
Canada
AtelierPaperAndOak
aweedmark
Canada Post Postcards
CaseyofAvalon
Chapters
Crave Paper
GreenBanana (see note below, Oct.4)
Hilary Morris
mixeddogart
Native Northwest Art
Postal Happy!!
sillustrates by Stephanie Simpson
The Friends of Algonquin Park
Pinkskull
Czech Republic
Papirovy tapir
Papertoe
Pohlednictví
Pohledy.cz
Estonia
Finland
Harjun Paperi
Inge Löök
Katja Saario
Korttien Talo
Mantelina
Minna Lehväslaiho
Minorpostcards
Postcard garden
Raijami
Viore
France
Arbre aux 100.000 rêves
Blue Art - Carte d’art
E-Mages
Hironwoods
Lescartesdelulu
Lulu Shop
Paper and Postcrosser
Papiers & Compagnie
Planète Images
Woodhi
Germany
Also see the collection of German online shops in the country subcategory, if you like.
Ampelmann.Shop, Berlin
Art und Form
Atelier Schiemann, Ruhrgebiet und Umgebung
Beatles Museum
Berlin Bleibt Bunt
Cityproducts
Danacards
drawings.by.yen
Duckomenta
Düsseldorf Shop
Edition A.B.Fischer
farbenspiel28
Fink Verlag
Formes Berlin
Geliebtes Chaos
Gutsch Verlag
Happy Postcards
Inkognito
Kartenküche
Kochformel
life-by-lines
Loyal Plush
Papermoon
Papersisters
Penn un Tint
PostalHeart
PostcardAdventure.eu
Postkartenshop Berlin
Posterxxl (for printing your own photos)
Pummel and Friends
Skowronski & Koch Verlag
Stayinspired.de
S.WERT
Greece
Anamnesia
I love Thessaloniki
Neanikon
Ploos Design
Samoshop
Etsy shops:
ahueofGreekblue
HandsOffMyDinosaur
Hungary
India
Auroville
ATLASkeeda
Destino
Dolls of India
Dreamz Cards
e Post Office
Gandhi Ashram
Heenas.in
Itokri
Kultureshop
Mario Miranda
NEST by Arpit Agarwal
Postally
Postcardbazaar
PostcardsVille
Postjunction
Read Bengali Books
Samyak
Shop Clues
Spiritual Postcards
Ireland
Badger & Blue
Kerry Climbing
Penpaling Paula
Real Ireland
Soul Links Postcards
The Wild Postcard Project
The Library Project - Ireland’s Art Bookshop
Japan
Keibunsha
Kyotobenrido
Let’s Gotochi
Loft
Yamaguchi Seikyokudo
Latvia
Duke Cards
NicePlace
Typicalpostcards
Lithuania
Agapics
Favorite Postcard
Lina Adi Photography
MonaiLT - Etsy
Nieko Rimto
Post Stone Postcards
Malaysia
ana tomy
Loka Made
Pigeon Postcard (closing down effective 8 June 2022)
Pos Malaysia
Stickerrific
Shopee Malaysia shops
Bunga dan Bintang
ByFlwrsArtwork
Hornbill Postcard
jazaloshoppe
joad233
KKKhor Collection
Little Dreamean
Loka Made
mintdumpling
Philately2u.com
Postcards Adventure
PostcardsCorner
Rancharc Studio
sembangsembang
slwong2828
The Original Market
Times Bookstore
We Post, We Care
Xinx Collection
Netherlands
Alternote
Amsterdam postcards
Artunlimited
By Kris
By Zenz
De Blauwe Maan
Decartograaf
De Blije Luiaard
De Verderkijker
DewyCreations
Dieren kaarten
Dille & Kamille
Elpapel.nl
Envycards
Essencio.nl
Fairyland
Goedkope ansichtkaarten
Happy postcrossing
Hip en stip
Hollandsekaart.nl
Kaartstudio
Leuke post
Muller wenskaarten
Mymagicards
Natuurlijke foto
Nikki Smits Webshop
Post & Papier
Postcards from Essie
Postzegel erop
Stationery heaven
Stationery world
Tinstarcompany
1001 kleuren.com
Norway
Philippines
Cynthia Bauzon-Arre
Papemelroti
Pinspired
Shopee Philippines shops
Pinaycrafter
JenellePamela
Pinspired
AMPC - A.M.Postcard Collection
Philippines VINTAGE Postcards
Papemelroti
Graciouslettersdesignsph
Poland
Delicious Postcards
House of Postcards
Napiszkartkę.pl
Postallove
Postrabbit
PostcardShop
1001 pocztówek
Portugal
Casa dos Postais
Dear Postal
Edições 19 de Abril
Edig Postal
New Jamp
Papyrus
Romania
Russia
AliceLand
Открытки Амели
Postal Jack
Сardamon
Сards shop
DarlingDove
DreamCards
ЕdenCards
Giraffepostcards
GrapeАrt
Kartinka24
Lovelycards
Мeleniza postcard
Moonpost
Mymagiccard RU and EN
МyPostland
Twinkle Card
Postal Jack
Марк Штемпель
Орех
Открытки ежика
Postal Shop
PostcardPress
Почтомания
Почтовый переулок
Cтранник
Открытки от улитки
Чердак
Марка
Магазин почтовых открытий Cardinbox
Почтовое бюро
PostCraft
PaperFOX
Мурр-почта
Postmans Bag
Моя чернильница
russia postcards
Старичок-почтовичок
PostCat
Открытки Белки/БелкаКардс
Магазины Etsy:
WOW-CARDS
ILLUSTORYART
красивая открытка kamila-la
Singapore
Spain
Carmen Saldana
Artimagen
La Postalera
[kamila-la]( красивая открытка (kamila-la.ru)
Sri Lanka
Online Store of SL Philatelic Bureau
Sweden
Adlibris
Jönköpings läns museum
Kalenderkungen
Kortbutiken
Postmuseum
Tradera
trivselkort
Upside
Etsy Shops
magicae
Switzerland
Appenzellerland
AS Verlag
Bildreich
COSA-Verlag
freshfish
jjPostcards (Aviation Postcards)
Lightmotif Editions
Werd Verlag
The Postcard Society
Schöne Grüsse
Taiwan
Nisan Design (World Travel Postcards)
Turkey
a pinch of sketches
İkisatır
Kagito
Kartpostal Kutusu
Lösev
Paper Street Co.
Uranus (Cardbook)
Tristan da Cunha
United Kingdom
Anna Wright
Art on a Postcard
Book Depository (postcard boxes)
Brainbox Candy
British Library
Cardtoons Publications
Cavalier Postcards
The Curious Pancake
Dave Thompson Art
Festival Postcards
Hannah Longmuir
Kettle’s Yard
Lagom Design
Leeds Postcards
Love Your Location
Ohh deer
Paperchase
Papio Press
The Postal Adventures of Morris Mouse
The Postcard Store
Post Snail Press
Royal Mail (recent PHQ editions)
Salts Mill Shop
Sugar & Sloth
Victoria & Albert Museum
The Wallich (currently not taking orders)
The Wooden Postcard Company
Wrendale Designs
Wuzci
Etsy shops
AlexiaClaire
BBIllustration
BonbiForest
BookishlyUK
emilymackenzie
FerneCreative
KatieAbey
TheLetteringTree
LinnetAndLark
LittlePaisleyDesigns
MogCherie
PatternAtelier
Potatosium
PrinterJohnson
RaahatIllustration
SophiasIllustration
TangleCrafts
tilliecm
TomHardwickDraws
ZoeSpryDesign
Cally Jane Studio
Search for more on
ebay - refine search to ‘auction only’ for second hand items
etsy - refine search to ‘UK shops’ for local sellers
notonthehighstreet
USA
Cafepress
Changing World/VisionWorks
Christopher Arndt Postcard Co.
Colorful Images
Current
Deviantart
Estate Sales (Usually Vintage)
GDBEE.ART
Internet Design Archive
JetPens
Laughing Elephant
MNJohn
Pike St. Press (Seattle-themed)
Pomegranate
Postcard Fair
Postcard Stop
Pumpernickel Press
Quantity Postcards
Tom Haseltine Photography
Zazzle
[MeganMarieMyersArt]
(www.etsy.com/shop/MeganMarieMyersArt)
Ebay shops
PostcardsAndMore
Etsy shops
LouPaper
Postcard Fair
Poxodd
MailByNina
Olechka Design
Archive Paper and Press
UnaPhoto
Surprise Postcards
FromNipponWithLove
Redbubble shops
Frank Moth
NineRavens
REALDesign
Isabella Marowski
Whole sale
Argonaut
Lantern Press