diff --git a/core/runtime/setup.rs b/core/runtime/setup.rs
index 17ac8398a..de3a68a9a 100644
--- a/core/runtime/setup.rs
+++ b/core/runtime/setup.rs
@@ -23,13 +23,10 @@ fn v8_init(
 
   let base_flags = concat!(
     " --wasm-test-streaming",
-    " --harmony-import-assertions",
-    " --harmony-import-attributes",
     " --no-validate-asm",
     " --turbo_fast_api_calls",
-    " --harmony-array-from_async",
-    " --harmony-iterator-helpers",
     " --harmony-temporal",
+    " --js-float16array",
   );
   let snapshot_flags = "--predictable --random-seed=42";
   let expose_natives_flags = "--expose_gc --allow_natives_syntax";
diff --git a/testing/unit/tc39_test.ts b/testing/unit/tc39_test.ts
index 841c81dfe..7d59ca2e8 100644
--- a/testing/unit/tc39_test.ts
+++ b/testing/unit/tc39_test.ts
@@ -39,8 +39,28 @@ test(function testIteratorHelpers() {
   }
 });
 
-// Verify that the "Temporal" proposal is enabled
-test(function testTemporalEnabled() {
+// Verify that "Set methods" proposal is enabled (https://github.com/tc39/proposal-set-methods)
+test(function testSetMethods() {
+  // @ts-expect-error: Not available in TypeScript yet
+  const a: Set<number> = new Set([1, 2, 3]).intersection(new Set([3, 4, 5]));
+  if (a.size !== 1 && !a.has(3)) {
+    fail("failed");
+  }
+});
+
+// Verify that the "Temporal" proposal is enabled (https://github.com/tc39/proposal-temporal)
+test(function testTemporal() {
   // @ts-expect-error: Not available in TypeScript yet
   assert(typeof Temporal !== "undefined");
 });
+
+// Verify that the "Float16Array" proposal is enabled (https://github.com/tc39/proposal-float16array)
+test(function testFloat16Array() {
+  // @ts-expect-error: Not available in TypeScript yet
+  const a = new Float16Array([Math.PI]);
+  assert(a[0] === 3.140625);
+  // @ts-expect-error: Not available in TypeScript yet
+  assert(typeof DataView.prototype.getFloat16 !== "undefined");
+  // @ts-expect-error: Not available in TypeScript yet
+  assert(typeof DataView.prototype.setFloat16 !== "undefined");
+});