@Nonnull
        @Override
        public <K> Map<BlockPosition, K> getAllWithKey(@Nonnull MetadataKey<K> key) {
            Objects.requireNonNull(key, "key");
            ImmutableMap.Builder<BlockPosition, K> ret = ImmutableMap.builder();
            this.cache.asMap().forEach((pos, map) -> map.get(key).ifPresent(t -> ret.put(pos, t)));
            return ret.build();
        }
The Metadata registries provided by helper.

These instances can be accessed through {@link Metadata}.
helper/src/main/java/me/lucko/helper/metadata/StandardMetadataRegistries.java