diff --git a/Rakefile b/Rakefile
index 72ce640e1..f4a27e447 100644
--- a/Rakefile
+++ b/Rakefile
@@ -36,6 +36,11 @@ task :validate => :parser do
       lib << "bigdecimal"
     end
 
+    if lib == ["yaml"]
+      lib << "dbm"
+      lib << "pstore"
+    end
+
     sh "#{ruby} #{rbs} #{lib.map {|l| "-r #{l}"}.join(" ")} validate --silent"
   end
 end
diff --git a/stdlib/yaml/0/dbm.rbs b/stdlib/yaml/0/dbm.rbs
new file mode 100644
index 000000000..a5eb02c6d
--- /dev/null
+++ b/stdlib/yaml/0/dbm.rbs
@@ -0,0 +1,221 @@
+# YAML Ain't Markup Language
+#
+# This module provides a Ruby interface for data serialization in YAML format.
+#
+# The YAML module is an alias of Psych, the YAML engine for Ruby.
+#
+# ## Usage
+#
+# Working with YAML can be very simple, for example:
+#
+#     require 'yaml'
+#     # Parse a YAML string
+#     YAML.load("--- foo") #=> "foo"
+#
+#     # Emit some YAML
+#     YAML.dump("foo")     # => "--- foo\n...\n"
+#     { :a => 'b'}.to_yaml  # => "---\n:a: b\n"
+#
+# As the implementation is provided by the Psych library, detailed documentation
+# can be found in that library's docs (also part of standard library).
+#
+# ## Security
+#
+# Do not use YAML to load untrusted data. Doing so is unsafe and could allow
+# malicious input to execute arbitrary code inside your application. Please see
+# doc/security.rdoc for more information.
+#
+# ## History
+#
+# Syck was the original for YAML implementation in Ruby's standard library
+# developed by why the lucky stiff.
+#
+# You can still use Syck, if you prefer, for parsing and emitting YAML, but you
+# must install the 'syck' gem now in order to use it.
+#
+# In older Ruby versions, ie. <= 1.9, Syck is still provided, however it was
+# completely removed with the release of Ruby 2.0.0.
+#
+# ## More info
+#
+# For more advanced details on the implementation see Psych, and also check out
+# http://yaml.org for spec details and other helpful information.
+#
+# Psych is maintained by Aaron Patterson on github:
+# https://github.com/ruby/psych
+#
+# Syck can also be found on github: https://github.com/ruby/syck
+#
+module YAML
+  # YAML + DBM = YDBM
+  #
+  # YAML::DBM provides the same interface as ::DBM.
+  #
+  # However, while DBM only allows strings for both keys and values,
+  # this library allows one to use most Ruby objects for values
+  # by first converting them to YAML. Keys must be strings.
+  #
+  # Conversion to and from YAML is performed automatically.
+  #
+  # See the documentation for ::DBM and ::YAML for more information.
+  class DBM < ::DBM
+    VERSION: ::String
+
+    # :call-seq:
+    #   ydbm[key] -> value
+    #
+    # Return value associated with +key+ from database.
+    #
+    # Returns +nil+ if there is no such +key+.
+    #
+    # See #fetch for more information.
+    def []: (String key) -> untyped
+
+    # :call-seq:
+    #   ydbm[key] = value
+    #
+    # Set +key+ to +value+ in database.
+    #
+    # +value+ will be converted to YAML before storage.
+    #
+    # See #store for more information.
+    def []=: (String key, untyped val) -> untyped
+
+    # :call-seq:
+    #   ydbm.fetch( key, ifnone = nil )
+    #   ydbm.fetch( key ) { |key| ... }
+    #
+    # Return value associated with +key+.
+    #
+    # If there is no value for +key+ and no block is given, returns +ifnone+.
+    #
+    # Otherwise, calls block passing in the given +key+.
+    #
+    # See ::DBM#fetch for more information.
+    def fetch: (String keystr, ?untyped? ifnone) { (untyped) -> untyped } -> untyped
+
+    # Deprecated, used YAML::DBM#key instead.
+    # ----
+    # Note:
+    # YAML::DBM#index makes warning from internal of ::DBM#index.
+    # It says 'DBM#index is deprecated; use DBM#key', but DBM#key
+    # behaves not same as DBM#index.
+    #
+    def index: (String keystr) -> untyped
+
+    # :call-seq:
+    #   ydbm.key(value) -> string
+    #
+    # Returns the key for the specified value.
+    def key: (String keystr) -> String
+
+    # :call-seq:
+    #   ydbm.values_at(*keys)
+    #
+    # Returns an array containing the values associated with the given keys.
+    def values_at: (*untyped keys) -> Array[untyped]
+
+    # :call-seq:
+    #   ydbm.delete(key)
+    #
+    # Deletes value from database associated with +key+.
+    #
+    # Returns value or +nil+.
+    def delete: (String key) -> untyped
+
+    def delete_if: () { (untyped, untyped) -> untyped } -> untyped
+
+    # :call-seq:
+    #   ydbm.reject { |key, value| ... }
+    #
+    # Converts the contents of the database to an in-memory Hash, then calls
+    # Hash#reject with the specified code block, returning a new Hash.
+    def reject: () { (untyped, untyped) -> untyped } -> Hash[untyped, untyped]
+
+    def each_pair: () { (untyped, untyped) -> untyped } -> untyped
+
+    def each_value: () { (untyped) -> untyped } -> untyped
+
+    # :call-seq:
+    #   ydbm.values
+    #
+    # Returns an array of values from the database.
+    def values: () -> untyped
+
+    # :call-seq:
+    #   ydbm.has_value?(value)
+    #
+    # Returns true if specified +value+ is found in the database.
+    def has_value?: (untyped val) -> (::TrueClass | ::FalseClass)
+
+    # :call-seq:
+    #   ydbm.invert -> hash
+    #
+    # Returns a Hash (not a DBM database) created by using each value in the
+    # database as a key, with the corresponding key as its value.
+    #
+    # Note that all values in the hash will be Strings, but the keys will be
+    # actual objects.
+    def invert: () -> Hash[untyped, untyped]
+
+    # :call-seq:
+    #   ydbm.replace(hash) -> ydbm
+    #
+    # Replaces the contents of the database with the contents of the specified
+    # object. Takes any object which implements the each_pair method, including
+    # Hash and DBM objects.
+    def replace: (Hash[untyped, untyped] | DBM hsh) -> YAML::DBM
+
+    # :call-seq:
+    #   ydbm.shift -> [key, value]
+    #
+    # Removes a [key, value] pair from the database, and returns it.
+    # If the database is empty, returns +nil+.
+    #
+    # The order in which values are removed/returned is not guaranteed.
+    def shift: () -> (Array[untyped] | untyped)
+
+    # :call-seq:
+    #   ydbm.select { |key, value| ... }
+    #   ydbm.select(*keys)
+    #
+    # If a block is provided, returns a new array containing [key, value] pairs
+    # for which the block returns true.
+    #
+    # Otherwise, same as #values_at
+    def select: (*untyped keys) { (untyped, untyped) -> untyped } -> Array[untyped]
+
+    # :call-seq:
+    #   ydbm.store(key, value) -> value
+    #
+    # Stores +value+ in database with +key+ as the index. +value+ is converted
+    # to YAML before being stored.
+    #
+    # Returns +value+
+    def store: (String key, untyped val) -> untyped
+
+    # :call-seq:
+    #   ydbm.update(hash) -> ydbm
+    #
+    # Updates the database with multiple values from the specified object.
+    # Takes any object which implements the each_pair method, including
+    # Hash and DBM objects.
+    #
+    # Returns +self+.
+    def update: (Hash[untyped, untyped]) -> YAML::DBM
+
+    # :call-seq:
+    #   ydbm.to_a -> array
+    #
+    # Converts the contents of the database to an array of [key, value] arrays,
+    # and returns it.
+    def to_a: () -> Array [untyped]
+
+    # :call-seq:
+    #   ydbm.to_hash -> hash
+    #
+    # Converts the contents of the database to an in-memory Hash object, and
+    # returns it.
+    def to_hash: () -> Hash[untyped, untyped]
+  end
+end
diff --git a/stdlib/yaml/0/store.rbs b/stdlib/yaml/0/store.rbs
new file mode 100644
index 000000000..3a2ac3979
--- /dev/null
+++ b/stdlib/yaml/0/store.rbs
@@ -0,0 +1,53 @@
+# YAML::Store provides the same functionality as PStore, except it uses YAML to
+# dump objects instead of Marshal.
+#
+# ## Example
+#
+#     require 'yaml/store'
+#
+#     Person = Struct.new :first_name, :last_name
+#
+#     people = [Person.new("Bob", "Smith"), Person.new("Mary", "Johnson")]
+#
+#     store = YAML::Store.new "test.store"
+#
+#     store.transaction do
+#       store["people"] = people
+#       store["greeting"] = { "hello" => "world" }
+#     end
+#
+# After running the above code, the contents of "test.store" will be:
+#
+#     ---
+#     people:
+#     - !ruby/struct:Person
+#       first_name: Bob
+#       last_name: Smith
+#     - !ruby/struct:Person
+#       first_name: Mary
+#       last_name: Johnson
+#     greeting:
+#       hello: world
+#
+class YAML::Store < ::PStore
+  # Creates a new YAML::Store object, which will store data in `file_name`. If the
+  # file does not already exist, it will be created.
+  #
+  # YAML::Store objects are always reentrant. But if *thread_safe* is set to true,
+  # then it will become thread-safe at the cost of a minor performance hit.
+  #
+  # Options passed in through `yaml_opts` will be used when converting the store
+  # to YAML via Hash#to_yaml().
+  #
+  def initialize: (*untyped o) -> YAML::Store
+
+  def dump: (untyped table) -> String
+
+  def empty_marshal_checksum: () -> String
+
+  def empty_marshal_data: () -> String
+
+  def load: (String) -> untyped
+
+  def marshal_dump_supports_canonical_option?: () -> ::FalseClass
+end