Scrapy - Scrapy | A Fast and Powerful Scraping and Web Crawling Framework
Clearbit - Clearbit provides Business Intelligence APIs
StormCrawler - StormCrawler is an open source SDK for building distributed web crawlers with Apache Storm.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
Apache Nutch - Apache Nutch is a highly extensible and scalable open source web crawler software project.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.