AWS EC2 has a wide range of use cases since almost everything can be configured when using this service. The most common use cases of AWS EC2 are:
Hosting web sites
Developing and testing applications or complex environments
High performance computing
Disaster recovery
General use cases of AWS Lambda:
Automating tasks
Processing objects uploaded to Amazon S3
Real-time log analyzing
Real-time filtering and transforming data
The complete list of available triggers:
API Gateway
AWS IoT
Alexa Skills Kit
Alexa Smart Home
Application Load Balancer
CloudFront
CloudWatch Events
CloudWatch Logs
CodeCommit
Cognito Sync Trigger
DynamoDB
Kinesis
S3
SNS
SQS