In my experience, Accenture is the big body shop. I've worked at companies that outsource tech strategy, new system requirements / scoping, delivery and development, and post deployment support and maintenance 100% to Accenture.

There are regional hubs they have (I've worked with Philippines and India and heard of Eastern Europe) for the support and maintenance.

There are some back office financial shared services (e.g., AP / AR / cutting POs) that they also support. I wouldn't be surprised if there was more.

Accenture can give you everything from the PowerPoint slides up to the people that will be seconded or placed in your organization as contingent workers / contractors.

That's Big 3 like McKinsey, and yes, notes sent to India, India turns them into powerpoints, team on the engagement has the powerpoints by the next morning (apparently execs don't even read something that's not in a powerpoint—they'll do this with stuff that's only ever going to be emailed, never presented)