Halo List is described as 'Get the latest cleantech and impact-related companies, jobs, markets, trends and ideas to your inbox'. There are six alternatives to Halo List for Online / Web-based, iPhone and SaaS. The best alternative is AngelList, which is free. Other great apps like Halo List are Betapage (Free), CrunchBase (Freemium), StartupRanking (Freemium) and Y-Combinator (Free).
CrunchBase is the world’s most comprehensive dataset of startup activity and it’s accessible to everyone. Founded in 2007 by Mike Arrington, CrunchBase began as a simple crowd sourced database to track startups covered on TechCrunch.