One of the largest genomes belongs to a very small creature, Amoeba dubia. This protozoan genome has 670 billion units of DNA, or base pairs. The genome of a cousin, Amoeba proteus, has a mere 290 billion base pairs, making it 100 times larger than the human genome.
Human genome is 3000.000.000 base pair, if we publish it as a book it needs 1000 books of 1000 pages.
Smallest genome identified is from a Viroid family, Viroids are the smallest known pathogenic agents and on of the smallest belongs to the Grapevine yellow speckle viroid with 220 nucleotide and Rice yellow mottle virus satellite with 220 bp then avocado sunblotch viroid (ASBV) linear; genomic RNA with 247 BP size (https://www.ebi.ac.uk/genomes/viroid