PublicAPIs - Explore the largest API directory in the galaxy
Oracle NetSuite - NetSuite is the leading integrated cloud business software suite, including business accounting, ERP, CRM and ecommerce software.
The Unsplash API - No-limits, do-what-you-want API for access to 200K+ HD pics.
Odoo - An all-integrated business app suite to unleash your growth potential.
API List - A collective list of APIs. Build something.
Sage Intacct - Intacct is a cloud-based accounting and financial management system that is designed for the businesses of all levels.