This list is only a highlight of a few industry participants, just a tip of the iceberg. Click thru some of the websites listed, beginning with the Information Aggregators, and you will be exposed to a whole universe of players in the industry.
Information Aggregators:
The Mix Market (themix.org; mixmarket.org)
CGAP (cgap.org; microfinancegateway.org)
Marketplace:
Kiva, Loans that change lives. (kiva.org)
Micro Place, Invest Wisely. End Poverty. (Microplace.com)
- Jan 2014 note - they have stopped, sadly, accepting new investors.
Bill & Melinda Gates Foundation
Oikocredit
Calvert Foundation
Omidyar Network
Unitus
United Nations Capital Development Fund
Gray Ghost Ventures
Blue Orchid
Grameen Foundation
Rotary Clubs around the world
Service providers:
Microrate (microrate.com)
Micro-Credit ratings International (m-cril.com)
mfTransparency (mftransparency.org)
Planet Rating (planetrating.com)
Council of Microfinance Equity Funds (cmef.com)
EPTEAM education and microfinance at UCSD (epteam.com)