Common substances (acidic, neutral, or basic):
Acidic - aspirin, wine, lemon juice, vinegar, ammonium ions in hair dye (NH4+), urine (uric acid)
Basic - cloudy ammonia (NH3), antacid tablets, oven cleaners, blood (ph 7.35)
Neutral - water (distilled or pure for an exact ph of 7), sugar, salt...