As mentioned on the linking page, magnesium levels should not exceed .10% (.001).
Listed below are some adult dry cat foods that meet AAFCO standards....
(Association of American Feed Control Officials)
Waltham 0%
K/D 0%
C/D .07%
W/D .08%
Kirkland .08%
Science Diet , Orig. - .08%
Purina One .08%
Purina Special Care .08%
Friskies Special Diet .085%
Nutro Max .085%
Prescrip. Health Blend .09%
IAMS Orig. .095%
Golden Blend .10%
Feline Principle .10%
Select Balance .10%
Purina Mature .10%

AVOID FOODS THAT DON'T LIST MAGNESIUM LEVELS
9 Lives
Atta Cat
Deli Cat
Kit 'N Kaboodle
Meow Mix
Nu Pet
Whiskas (All)
Alley Cat
Chefs Blend
Friskies - Senior. Ocean Fish, Poultry Platter,Dental Diet, and Gourmet
Purina Cat Chow