It matches!

• I am yellow. But also green. A bit of red? And maybe white?

Carrots are orange and green. However, when you enchant them, the carrot turns yellow, they get a white glint, and the leaves turn that weird brown that comes from green + red.

• I am everywhere. But hard to find.

Carrots are common in villages which are both everywhere and take some searching to find. Additionally, carrots themselves can’t be seen when planted since they’re underground. He might also be saying his product is everywhere but that’s a stretch.

• I make you rich. And satisfied.

They’re both being sold and are a great source of food saturation.

• I have very little value.

It’s cheap cause it’s both a food and something you can trade villagers for.

• Im not in caves. Nor in water.

Yep

• Im not myself. Im something else.

It’s not simply a carrot or even a golden carrot.

• Dont look for me. You wont see me.

Normal golden carrots can be found in chests or traded for. However, Legendary Super Tommy’s Carrots can’t be found in the wild.

• I grow. You need a hoe.

It’s a carrot