All cucurbit family and annual vegetables
Tomatoes
If by this you mean what fruits are customarily called vegetables, two of the most common are the tomato and the cucumber.
the two most grown goods in Egypt were wheat and barley
Pashtun and Tajik are the two most common tribes.
Semi-annual vegetables are those that typically have two growing seasons within a year. Examples include broccoli, cauliflower, and cabbage, which can be planted in early spring for a summer harvest and again in late summer for a fall harvest. Other examples are spinach and kale, which can thrive in both spring and fall. These vegetables benefit from cooler temperatures, making them ideal for semi-annual cultivation.
I know of several people who own small businesses that hold their annual payday once every two or so weeks on a Thursday or a Friday. These are two extremely common days.
The two most common temperature scales are... Celsius and Kelvin. *For Canada.*
The two most common systems of units are cgs and SI systems
Oxygen and silicon are the two most abundant elements found in the most common minerals. The most common minerals found on Earth are silicates.
The two most common religious systems in Nigeria are Islam and Christianity.
The two most common types of compressors are the positive-displacement and the velocity or dynamic.
The two most common elements in the Universe, and in most stars are - in that order - hydrogen and helium (elements #1 and #2).
Black and Red are two most common colors.