@Hyolobrika It is generally advised everyone, regardless of diet, supplements Vitamin D during the winter months. It is also advised to supplement year-round if someone lives near the poles due to inadequate sunlight. https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/

Vegetarians generally don't need to supplement anything other than the above. There's nothing essential in meat that you can't get elsewhere. B12 deficiency is balanced across dietary groups but has been decreasing overall, due to the increased availability of cost-effective supplementation.

@alex