Affinity is a relationship management platform that helps you leverage relationship intelligence to expand your network, support your portfolio, and increase proprietary deal flow.affinity.co
Salesforce specializes in customer relationship management. It can easily scale to enterprise level, but is more expensive than other options.
The HubSpot free CRM is free and intuitive. They offer a startup program for discounted rates, if your needs marketing needs exceed their free tier.
Pilot offers bookkeeping, tax, and CFO services for growing businesses. Your favorite tools integrate with Pilot so that everything is kept effortlessly up to date, including Stripe, Quickbooks, Square, Shopify, Gusto, Expensify, Bill.com, and others.