W3Counter - W3Counter lists visits, referrals, browser versions, resolution, and operating systems used to view a site.
Leadfeeder - Leadfeeder converts your website visitors into sales. Connect your website's Google Analytics to Leadfeeder and unlock the power of seeing who`s visiting your site!
HitWebCounter - HitWebCounter is a free website visitor counter.
Clearbit - Clearbit provides Business Intelligence APIs
ShinyStat - ShinyStat is a web tracker with visits and online counter.
Lead Forensics - B2B website analytics and lead generation.