CRM for Current Clients (not to get new clients)

I've been struggling to find a CRM that is NOT focused on sales and acquiring new clients.

I recruit independent contractors and all my recruiting is by referral. Referrals improve by communicating more often and more effectively with the contractors with whom I already work.

With every CRM system I can find, I find I'm trying to delete almost all of the pre-programmed fields and shoehorn what I really want in it: tracking and automating communication with my current clients.

Is there anything out there that's already set up to nurture current clients?

PS – I'm definitely NOT looking for a "ticketing system" to respond to inquiries.