Cardigans! Cardigans were my go-to when I had to work in an office. Get some higher neck camis or t-shirts, like this one from Hanes and mix them up with cardigans (you can get them at different price points from Walmart, Old navy, Banana republic, LOFT, etc). I actually like the Amazon brand clothes too, and with their wardrobe feature you can try them on and return everything you don't like.
Ann Taylor has some nice clothes for work, they even have a "business formal" or "business casual" filter on their website. But they are pretty expensive.