Is there a good example service that uses S3 and CognitoIdentityPools/UserPools?

I am new to AWS and serverless. Last weekend I started implement a very basic javascript API that uses S3 to store and retrieve objects and Cognito Identity and User Pools for authentication.

I tried to find a simple example service that could be used as a template or model for my API, but could not find any. I then read lots of documentation and looked at several examples that were somewhat similar to my service, but I still had to spend several hours in quite frustrating debugging of serverless.yml and the function definitions before I finally got my lambda functions running and accessing S3 correctly.

I still wonder whether there are some good example services that use S3 and Cognito? Could you suggest one?