Vitamins A and D are fat soluble, so your body stores any excess rather than getting rid of it. It is easy to get too much of these vitamins by taking supplements. A especially. Alpha and Beta carotene (pro-vitamin A, which your body converts to vitamin A as needed, and thus there is no risk of overdosing) is found in many yellow and orange fruits and veggies.
As Offense mentioned, the best source of vitamin D is the sun. And it doesn't take a lot, since humans have evolved to efficiently produce vitamin D (which is actually a hormone) in response to sun exposure. Just 15 minutes of exposure most days of the week for 3/4 of the year is enough.
Mushrooms also contain vitamin D.
D2 (ergocalciferol), which is the vegan version of vitamin D, can be found in enriched foods, and in supplements you can get at www.veganessentials.com
. D3 (cholicalciferol) is the non-vegan version of vitamin D. Think "D3 is not for me. D2 for me and you." (that helps me remember which is which!)