AWS provides lists of IP ranges for its services, and documentation if available to "Get all IPv4 addresses for a specific service in a specific Region". However, services is the list are hardly specific.
Is there a way to retrieve IP ranges specifically used for AWS Lambda?
Nope, AWS does not list the IP addresses used for Lambda unlike S3.
If you want Lambda IP's so as to whitelist them in accessing your servers/gateways/endpoints, better solution is to place the Lambda functions in private subnets in a VPC. Attach NAT Gateways to the VPC(ofcourse Elastic IPs are attached to NAT GW)
Then you can whitelist these Elastic IPs