Только фото (растровые) изображения:

Dreamstime

Creative Commons Search

Free Digital Photos

Foter

Free Images

Free Range Stock

StockPhotos.io

Free Photos Bank

ImageFree

IM Free

Morguefile

Public Domain Pictures

Stockvault

Rgbstock

Getty Images

Ancestry Images

BigFoto

Gratisography

Death to The Stock Photo

FreeMediaGoo

Hubspot

Compfight

iStock

Can We Image

Little Visuals

New Old Stock

PicJumbo

Pickupimage

Superfamous

Unsplash