Application Load Balancer (ALB) : ALB allows routing based on port numbers. It can also route requests to Lambda, and it can direct requests to many ports on the target. Application Load Balancer supports only layer 7 - HTTP/2 and Web Sockets. It can return primary responses on its own so the server can be set free of replying to redundant requests. ALB find use in Microservices and application
Network Load Balancer (NLB) : Network Load Balancer supports Layer 4 that is TCP and UDP. It is faster and high-performance since it is lower in the OSI model. It uses static IPs and can also be assigned elastic IPs. An example would be real-time data streaming or video streaming.
Classic Load Balancer (CLB) or Elastic Load Balancer (ELB version1) : ELB is the oldest Load balancer and the only one which offers application-specific sticky session cookies. It works both on Layer 7 and Layer 4. ELB also supports EC2-Classic.
