Google Tag Manager - Google Tag Manager helps make tag management simple, easy and reliable by allowing marketers and webmasters to deploy website tags all in one place.
V12 Data - V12 Data offers rich data sets with verified addresses and emails for personalized marketing campaigns.
Segment - We make customer data simple.
Lotame - Make your data actionable, learn about your most valuable customers, improve ROI by targeting the right audience and increase relevance across screens.
RudderStack - Open-Source Customer Data Platform
Google Audience Center - 3 votes and 6 comments so far on Reddit