Because terminal > web interface

To briefly list all env (one env by line):
aws elasticbeanstalk describe-environments|jq -r '.Environments|.[]| [.ApplicationName, .EnvironmentName, .VersionLabel, .Status, .CNAME] | @csv'|sort

To get all info about one env (pass EnvironmentName):
aws elasticbeanstalk describe-environments --environment-names toto-prod

List all subnets:
aws ec2 describe-subnets|jq -r '.Subnets|.[]|.SubnetId'

List all ec2 instanceId:
aws ec2 describe-instances|jq -r '.Reservations|.[]|.Instances|.[]|.InstanceId'

List all ec2 instanceId with its associated subnetId:
aws ec2 describe-instances|jq -r '.Reservations|.[]|.Instances|.[]|[.InstanceId, .SubnetId] | @csv'