Like this @mattbdev ?

worldedit-core/src/main/java/com/sk89q/worldedit/world/block/BlockType.java

@@ -47,6 +47,7 @@ import java.util.stream.IntStream;
 import javax.annotation.Nullable;
 
 public class BlockType implements FawePattern, Keyed {
+    protected static final BlockType DUMMY = new BlockType();
 
     public static final NamespacedRegistry<BlockType> REGISTRY = new NamespacedRegistry<>("block type");
 
@@ -56,6 +57,12 @@ public class BlockType implements FawePattern, Keyed {
     private boolean initItemType;
     private ItemType itemType;
 
+    // Dummy
+    private BlockType() {
+        this.id = null;
+        this.settings = null;
+    }
+
     protected BlockType(String id, int internalId, List<BlockState> states) {
         int i = id.indexOf("[");
         this.id = i == -1 ? id : id.substring(0, i);