I don't have a "stack" yet but I have run across a few tools in my searches. One, Rasa.io, seems particularly interesting and not so pricey as 12,500 contacts are currently $142/mo. The other, Encharge, seems to be priced similarly. For me, neither would have worked. Rasa uses Fb, Twitter etc to pull from and I prefer more obscure sources and Encharge does the emailing for you...it's not self hosted. But both look like they might fit your criteria. hth