B12 vitamin is primarily found in animal-based foods, making it a challenge for vegetarians and vegans to obtain adequate amounts naturally. However, there are some plant-based sources that can provide B12 or be fortified with it. These include:

1. Fortified Plant Milks: Many plant-based milks like almond milk, soy milk, and oat milk are often fortified with B12.

2. Fortified Breakfast Cereals: Certain breakfast cereals are fortified with B12, which can be a good source for those following a plant-based diet.

3. Nutritional Yeast: Nutritional yeast is a popular B12 source for vegetarians and vegans. It has a cheesy flavor and can be sprinkled on dishes.

4. Fortified Plant-Based Meat Alternatives: Some meat alternatives made from plants are fortified with B12.

5. Supplements: B12 supplements are a reliable way for vegetarians and vegans to meet their B12 needs. It's important to consult a healthcare professional to determine the right dosage.

Ensuring an adequate intake of B12 is crucial for overall health, particularly for those on a vegetarian or vegan diet.