EFA Support in G6 Instance

Based on the available information, the g6e.24xlarge instance type supports Elastic Fabric Adapter (EFA). EFA is a network interface for Amazon EC2 instances that enables high levels of internode communications, which is particularly useful for High Performance Computing (HPC) applications and applications using Message Passing Interface (MPI) libraries at scale on AWS.

For instances that support multiple network cards (like many of the larger instance types), EFA and EFA-only network interfaces count as a network interface. You can assign only one EFA or EFA-only network interface per network card, and the primary network interface cannot be an EFA-only network interface.

If you want to see a complete list of instance types that support EFAs in a specific AWS Region, you can run the AWS CLI command:

aws ec2 describe-instance-types --region [region] --filters Name=network-info.efa-supported,Values=true --query "InstanceTypes[*].[InstanceType]" --output text | sort

This command will return all instance types that support EFA in the specified region, which you can then cross-reference with the available G6 instance types.
Sources
Elastic network interfaces - Amazon Elastic Compute Cloud
Elastic Fabric Adapter - AWS Batch