Find and entity with unknown entity_type

Hi there,
Is there any way to find an entity by a field, but not knowing the entity_type?
I though about looping all the entities by getting the schemas, but that’s… quite some entities… is there any better way??
I have a number, I know that number is an “order” number and is unique, but a lot of my entities across several projects have that field. How can I find that entity without knowing which entity type is?