Are there multivitamins designed for those with a vegan diet? Such that they have proportionally more of the vitamins vegans are deficient in (B12, calcium, etc.)?
If you are eating a well-balanced diet, you may be getting sufficient nutrients from what you are already eating. The last two doctors I've discussed this with (because I was concerned myself) said I likely had enough of most of the vitamins in a multivitamin, and instead suggested taking only supplements for the vitamins I was deficient in. (I am now taking a B12 vitamin only). So, it may be helpful to look into what you are not getting enough of (can have blood work done to see levels of nutrients in your system, if that is available to you) and then targeting vitamins that have only what you need.