Eosin-methylen blue agar (EMB) that contains Methylene Blue which is toxic for Gram-positive bacteria allowing only the growth (thus selecting) of Gram Negative bacteria.
YM ( Yeast and Mold ) which has a low PH , deterring bacterial growth.
Blood Agar (used in Strep tests), which contains beef heart blood which becomes transparent in the presence of hemolytic '' Streptococcus ''.
