diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index f22da59a376..a1f6fd4f938 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -710,7 +710,7 @@ cc_test(
     deps = [
         ":raw_hash_set",
         ":tracked",
-        "//absl/base:core_headers",
+        "//absl/base:config",
         "@com_google_googletest//:gtest_main",
     ],
 )
@@ -741,9 +741,9 @@ cc_test(
     deps = [
         ":layout",
         "//absl/base:config",
-        "//absl/base:core_headers",
         "//absl/log:check",
         "//absl/types:span",
+        "//absl/utility",
         "@com_google_googletest//:gtest_main",
     ],
 )
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index 39d95e029ea..f3443a6632e 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -754,9 +754,9 @@ absl_cc_test(
   COPTS
     ${ABSL_TEST_COPTS}
   DEPS
+    absl::config
     absl::raw_hash_set
     absl::tracked
-    absl::core_headers
     GTest::gmock_main
 )
 
@@ -789,8 +789,8 @@ absl_cc_test(
     absl::layout
     absl::check
     absl::config
-    absl::core_headers
     absl::span
+    absl::utility
     GTest::gmock_main
 )
 
diff --git a/absl/container/internal/layout_test.cc b/absl/container/internal/layout_test.cc
index ce599ce79f1..ae55cf7e51c 100644
--- a/absl/container/internal/layout_test.cc
+++ b/absl/container/internal/layout_test.cc
@@ -19,8 +19,12 @@
 #include <stddef.h>
 
 #include <cstdint>
+#include <cstring>
+#include <initializer_list>
 #include <memory>
-#include <sstream>
+#include <ostream>
+#include <string>
+#include <tuple>
 #include <type_traits>
 
 #include "gmock/gmock.h"
@@ -28,6 +32,7 @@
 #include "absl/base/config.h"
 #include "absl/log/check.h"
 #include "absl/types/span.h"
+#include "absl/utility/utility.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
diff --git a/absl/container/internal/raw_hash_set_allocator_test.cc b/absl/container/internal/raw_hash_set_allocator_test.cc
index e73f53fd637..53cc5180a25 100644
--- a/absl/container/internal/raw_hash_set_allocator_test.cc
+++ b/absl/container/internal/raw_hash_set_allocator_test.cc
@@ -12,10 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <cstddef>
+#include <cstdint>
+#include <functional>
 #include <limits>
-#include <scoped_allocator>
+#include <memory>
+#include <ostream>
+#include <set>
+#include <type_traits>
+#include <utility>
 
 #include "gtest/gtest.h"
+#include "absl/base/config.h"
 #include "absl/container/internal/raw_hash_set.h"
 #include "absl/container/internal/tracked.h"
 
diff --git a/absl/flags/BUILD.bazel b/absl/flags/BUILD.bazel
index 50bf387cd6b..65577a9be24 100644
--- a/absl/flags/BUILD.bazel
+++ b/absl/flags/BUILD.bazel
@@ -266,8 +266,8 @@ cc_library(
         ":reflection",
         "//absl/base:config",
         "//absl/base:core_headers",
-        "//absl/container:flat_hash_map",
         "//absl/strings",
+        "//absl/synchronization",
     ],
 )
 
diff --git a/absl/flags/CMakeLists.txt b/absl/flags/CMakeLists.txt
index b20463f50bb..a535b55e843 100644
--- a/absl/flags/CMakeLists.txt
+++ b/absl/flags/CMakeLists.txt
@@ -243,7 +243,6 @@ absl_cc_library(
     absl::flags_private_handle_accessor
     absl::flags_program_name
     absl::flags_reflection
-    absl::flat_hash_map
     absl::strings
     absl::synchronization
 )
diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc
index 13852e14678..8b169bcdc2c 100644
--- a/absl/flags/internal/usage.cc
+++ b/absl/flags/internal/usage.cc
@@ -27,7 +27,10 @@
 #include <utility>
 #include <vector>
 
+#include "absl/base/attributes.h"
 #include "absl/base/config.h"
+#include "absl/base/const_init.h"
+#include "absl/base/thread_annotations.h"
 #include "absl/flags/commandlineflag.h"
 #include "absl/flags/flag.h"
 #include "absl/flags/internal/flag.h"
@@ -40,6 +43,8 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_split.h"
 #include "absl/strings/string_view.h"
+#include "absl/strings/strip.h"
+#include "absl/synchronization/mutex.h"
 
 // Dummy global variables to prevent anyone else defining these.
 bool FLAGS_help = false;
diff --git a/absl/hash/BUILD.bazel b/absl/hash/BUILD.bazel
index 4346fc4954e..a520ae62f53 100644
--- a/absl/hash/BUILD.bazel
+++ b/absl/hash/BUILD.bazel
@@ -85,9 +85,13 @@ cc_test(
         "//absl/container:flat_hash_set",
         "//absl/container:node_hash_map",
         "//absl/container:node_hash_set",
+        "//absl/memory",
         "//absl/meta:type_traits",
         "//absl/numeric:int128",
         "//absl/strings:cord_test_helpers",
+        "//absl/strings:string_view",
+        "//absl/types:optional",
+        "//absl/types:variant",
         "@com_google_googletest//:gtest_main",
     ],
 )
diff --git a/absl/hash/CMakeLists.txt b/absl/hash/CMakeLists.txt
index 65fd2a5f70e..438c1cda85f 100644
--- a/absl/hash/CMakeLists.txt
+++ b/absl/hash/CMakeLists.txt
@@ -68,18 +68,22 @@ absl_cc_test(
   COPTS
     ${ABSL_TEST_COPTS}
   DEPS
+    absl::btree
     absl::cord_test_helpers
-    absl::hash
-    absl::hash_testing
     absl::core_headers
-    absl::btree
     absl::flat_hash_map
     absl::flat_hash_set
+    absl::hash
+    absl::hash_testing
+    absl::int128
+    absl::memory
+    absl::meta
     absl::node_hash_map
     absl::node_hash_set
+    absl::optional
     absl::spy_hash_state
-    absl::meta
-    absl::int128
+    absl::string_view
+    absl::variant
     GTest::gmock_main
 )
 
diff --git a/absl/hash/hash_benchmark.cc b/absl/hash/hash_benchmark.cc
index 8712a01ccaa..916fb620c6b 100644
--- a/absl/hash/hash_benchmark.cc
+++ b/absl/hash/hash_benchmark.cc
@@ -12,7 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
 #include <string>
+#include <tuple>
 #include <type_traits>
 #include <typeindex>
 #include <utility>
diff --git a/absl/hash/hash_test.cc b/absl/hash/hash_test.cc
index a0e2e4a7113..111f375b70c 100644
--- a/absl/hash/hash_test.cc
+++ b/absl/hash/hash_test.cc
@@ -17,42 +17,36 @@
 #include <algorithm>
 #include <array>
 #include <bitset>
+#include <cstddef>
 #include <cstdint>
+#include <cstdlib>
 #include <cstring>
-#include <deque>
-#include <forward_list>
 #include <functional>
 #include <initializer_list>
-#include <iterator>
+#include <ios>
 #include <limits>
-#include <list>
-#include <map>
 #include <memory>
-#include <numeric>
-#include <random>
+#include <ostream>
 #include <set>
 #include <string>
 #include <tuple>
 #include <type_traits>
 #include <unordered_map>
-#include <unordered_set>
 #include <utility>
 #include <vector>
 
-#include "gmock/gmock.h"
 #include "gtest/gtest.h"
-#include "absl/container/btree_map.h"
-#include "absl/container/btree_set.h"
-#include "absl/container/flat_hash_map.h"
+#include "absl/base/config.h"
 #include "absl/container/flat_hash_set.h"
-#include "absl/container/node_hash_map.h"
-#include "absl/container/node_hash_set.h"
 #include "absl/hash/hash_testing.h"
 #include "absl/hash/internal/hash_test.h"
 #include "absl/hash/internal/spy_hash_state.h"
+#include "absl/memory/memory.h"
 #include "absl/meta/type_traits.h"
-#include "absl/numeric/int128.h"
 #include "absl/strings/cord_test_helpers.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "absl/types/variant.h"
 
 #ifdef ABSL_HAVE_STD_STRING_VIEW
 #include <string_view>
diff --git a/absl/time/duration.cc b/absl/time/duration.cc
index 634e5d58455..bdb16e21092 100644
--- a/absl/time/duration.cc
+++ b/absl/time/duration.cc
@@ -55,8 +55,7 @@
 
 #include <algorithm>
 #include <cassert>
-#include <cctype>
-#include <cerrno>
+#include <chrono>  // NOLINT(build/c++11)
 #include <cmath>
 #include <cstdint>
 #include <cstdlib>
@@ -66,8 +65,9 @@
 #include <limits>
 #include <string>
 
+#include "absl/base/attributes.h"
 #include "absl/base/casts.h"
-#include "absl/base/macros.h"
+#include "absl/base/config.h"
 #include "absl/numeric/int128.h"
 #include "absl/strings/string_view.h"
 #include "absl/strings/strip.h"