A vast database of WMS, Tile Map Services etc is readily available for free, especially from government sources (United Kingdom, United States of America etc.) or agencies (e.g. FEMA) relating to useful information for companies and professionals (e.g. flood hazard maps, topographic maps).
You can find a list of such services (that will frequently be updated) below:
- USA: USGS Topo
- USA: FEMA National Flood Hazard Layer
- Australia: Queensland Globe
- Greece: Hellenic Cadastre