zotero.org
Zotero is a powerful, easy-to-use research tool that helps you gather, organize, and analyze sources and then share the results of your research.
LINK: https://www.zotero.org/
copernic.com
Copernic Agent is the client to assist in searching the web. There are other very useful products as well, also to manage downloaded data.
indexmundi.com/search.html
IndexMundi is a data portal that gathers facts and statistics from multiple sources and turns them into easy to use visuals.
precisionhawk.com/satellite
It has got satellite images and aerial photos. You can view and search online for free.
mapmart.com
MapMart offers a variety of high, medium and low resolution satellite imagery datasets for nearly every location on the earth.
LINK: http://www.mapmart.com/
google.com/earth
Google Earth lets you fly anywhere on Earth to view satellite imagery, maps, terrain, 3D buildings, from galaxies in outer space to the canyons of the ocean.
zoom.earth
Zoom into new NASA satellite and aerial images of the Earth, updated every day.
LINK: https://zoom.earth
rssmicro.com
RSS Micro is the Internet’s largest real time search engine and aggregator of RSS Feeds.
LINK: http://www.rssmicro.com/