Abu Dhabi SDI: https://sdi.abudhabi.ae/Sites/SDI/Navigation/EN/root.html
Andorra Geoportal: http://www.cartografia.ad
Bahrain SDI: http://www.bsdi.gov.bh/Achivements_ogc_page2.aspx
Egyptian Spatial Data Infrastructure (SDI): http://www.arcgis.com/home/item.html?id=0807d0fa91954451b49f31302273c75b
FGDC (USA) Data and Services Clearning House: https://www.fgdc.gov/dataandservices
FIND - Australian spatial data catalogue: http://find.ga.gov.au
French NSDI Geoportal: http://www.geoportail.gouv.fr
GeoGratis - Canadian geoportal from Natural Resources Canada:http://www.nrcan.gc.ca/earth-sciences/geography/topographic-information/free-data-geogratis/11042
GeoPlatform - US authoritative spatial data portal: http://www.geoplatform.gov/overview-page
GeoSUR (SDI Portal of Latin American and Caribbean agencias): http://www.geosur.info
GGPM - Global GeoPortal Map (official geoportals for each counutry in the world): http://evetion.nl/portal
IDEE - Spanish National SDI Portal (Infraestructura de Datos Espaciales de Espana): http://www.idee.es
INSPIRE GeoPortal (pan-European portal): http://inspire-geoportal.ec.europa.eu
LINZ Data Service (Land Information New Zealand): https://data.linz.govt.nz
Portuguese NSDI Geoportal: http://snig.igeo.pt/Portal
UN-GGIM Links to national SDI initiatives and portals (16 countries):http://ggim.un.org/sdi.html