1. Monera (also known as Bacteria): This kingdom includes all prokaryotic organisms, which are single-celled organisms that lack a nucleus and other membrane-bound organelles. Bacteria are incredibly diverse and can be found in virtually every environment on Earth.

2. Protista (also known as Protoctista): This kingdom is a diverse group of eukaryotic microorganisms, which are single-celled or multicellular organisms that have a nucleus and other membrane-bound organelles. Protists include a wide variety of organisms, such as algae, protozoa, slime molds, and water molds.

While some fungi are microscopic, the kingdom Fungi also includes macroscopic organisms like mushrooms and molds.