When creating AWS CloudFormation templates that have DB instance type parameters, populating the allowed values list to validate the instance type string can be tedious.

Here are some sets of DB instance types that can be copy-pasted into the "AllowedValues" field of your AWS CloudFormation DB instance type parameter.

View more info on these instance types: Amazon RDS Instance Types

My Most Commonly Used DB Instance Set

[
  "db.t3.micro", "db.t3.small", "db.t3.medium", "db.t3.large", "db.t3.xlarge", "db.t3.2xlarge",
  "db.m5.large", "db.m5.xlarge", "db.m5.2xlarge", "db.m5.4xlarge", "db.m5.12xlarge", "db.m5.24xlarge"
]

General Purpose

[
  "db.t3.micro", "db.t3.small", "db.t3.medium", "db.t3.large", "db.t3.xlarge", "db.t3.2xlarge",
  "db.t2.micro", "db.t2.small", "db.t2.medium", "db.t2.large", "db.t2.xlarge", "db.t2.2xlarge",
  "db.m5.large", "db.m5.xlarge", "db.m5.2xlarge", "db.m5.4xlarge", "db.m5.12xlarge", "db.m5.24xlarge",
  "db.m4.large", "db.m4.xlarge", "db.m4.2xlarge", "db.m4.4xlarge", "db.m4.10xlarge", "db.m4.16xlarge"
]

T Class General Purpose DB Instance Types

[
  "db.t3.micro", "db.t3.small", "db.t3.medium", "db.t3.large", "db.t3.xlarge", "db.t3.2xlarge",
  "db.t2.micro", "db.t2.small", "db.t2.medium", "db.t2.large", "db.t2.xlarge", "db.t2.2xlarge"
]

M Class General Purpose DB Instance Types

[
  "db.m5.24xlarge",
  "db.m4.large", "db.m4.xlarge", "db.m4.2xlarge", "db.m4.4xlarge", "db.m4.10xlarge", "db.m4.16xlarge"
]

Memory Optimized

[
  "db.r5.large", "db.r5.xlarge", "db.r5.2xlarge", "db.r5.4xlarge", "db.r5.12xlarge", "db.r5.24xlarge", 
  "db.r4.large", "db.r4.xlarge", "db.r4.2xlarge", "db.r4.4xlarge", "db.r4.8xlarge", "db.r4.16xlarge", 
  "db.x1e.xlarge", "db.x1e.2xlarge", "db.x1e.4xlarge", "db.x1e.8xlarge", "db.x1e.16xlarge", "db.x1e.32xlarge",
  "db.x1.16xlarge", "db.x1.32xlarge",
  "db.z1d.large", "db.z1d.xlarge", "db.z1d.2xlarge", "db.z1d.3xlarge", "db.z1d.6xlarge", "db.z1d.12xlarge"
]

R Class Memory Optimized DB Instance Types

[
  "db.r5.large", "db.r5.xlarge", "db.r5.2xlarge", "db.r5.4xlarge", "db.r5.12xlarge", "db.r5.24xlarge", 
  "db.r4.large", "db.r4.xlarge", "db.r4.2xlarge", "db.r4.4xlarge", "db.r4.8xlarge", "db.r4.16xlarge"
]

X Class Memory Optimized DB Instance Types

[
  "db.x1e.xlarge", "db.x1e.2xlarge", "db.x1e.4xlarge", "db.x1e.8xlarge", "db.x1e.16xlarge", "db.x1e.32xlarge",
  "db.x1.16xlarge", "db.x1.32xlarge"
]

Z Class Memory Optimized DB Instance Types

[
  "db.z1d.large", "db.z1d.xlarge", "db.z1d.2xlarge", "db.z1d.3xlarge", "db.z1d.6xlarge", "db.z1d.12xlarge",
]