Most AWS services' console/API are 1-1. Occasionally a console might offer some convenience features which are just a combination of API calls, but I'm not aware of any service that has functionality solely offered in the console. As the original comment touched on, this would be really unusual in AWS where most attention goes to the APIs/SDKs which are what larger customers use.
>but I'm not aware of any service that has functionality solely offered in the console
Historically, there have been some big ones, including some features related to pretty core services - I am fairly sure some autoscaling related features were console only for some time before an API was added. Instance limits were a console only feature for a year or so before DescribeEC2InstanceLimits was a thing.
It's not just historic examples, either.
Basically all of Quicksight outside of group/user management lacks an API today. Which is particularly annoying for some of my use cases, since the more technical folks generally will use Athena directly, and the people that want to use quicksight to examine the data are the ones that are less technical, which means needing other people to go and manually configure data sources, setup refresh schedules, etc. I'd love to be able to shove all of that into cloudformation and do it programmatically, but since it lacks APIs to begin with, I can't do it in cloudformation even as a custom resource via lambda.
There are definitely some API-only things. Mostly edge cases. For example, last week I ran into the fact that it's only possible to associate a Route 53 Hosted Zone with a VPC from a different account via the API.
