Standard Process Cataplex B and liver. I try to find beef that come from grass-fed cows. No growth hormones or lots of antibiotics and other stuff that is given to animals that can affect people.
Eat good meat as suggested, whole grains, free-range eggs, brown rice, good dairy products, nuts. You can get what you need from your food if you eat right. The only good sources of b12 are animal sources. The b1 you can get from the whole grains and nuts.