These are the places in which I like to shop. I am only stating places that I have already purchased from. I am not paid to make these reviews and I am not saying that everything the store has is modest. Unfortunately there is not one all-time store to find decent, beautiful, and modest clothing. I have had to search through hundreds with little results at time. Other times, I have a little more luck. Anyhow, I have compiled a list of stores that I like to shop at.

Department Stores:
Kohls
Boston Store
Maurices
Marshals
Dressbarn (has very good quality items and offers a good selection of dresses)

I shop at various thrift stores and vintage stores.

Online Shopping (My favorite):

Etsy - olesyamasiytina (I ordered a suit from her. She is a little pricey but the clothes are tailor made

and good quality. Since she custom makes everything, you can ask her to add length or to make something looser... It is worth a look!) xiaolizi (This is a woman from China who custom makes things as well. She is more affordable as well. I looked through her pages and I would say probably 90% of her clothing comes modest as is! I ordered a skirt from her and I am waiting for it. I will update this for quality when it arrives. *note* Chinese tailors have very good quality in their work, unlike the clothing in our department stores that says 'made in China' and is from a factory. I lived in China and so I have experience with Chinese tailors.)
Another website I have ordered from is Blueberry Hill Fashions
http://www.blueberryhillfashions.com/ While most of her clothing is not modest (most can be fixed by just adding a sweater), she has a few pieces and I have ordered from her before and she is very good to work with and I like the quality. I thought it was worth mentioning.
Chicwish https://www.chicwish.com/ (you all know I love this website for skirts!)
Another more expensive (but amazing quality) is JPeterman https://www.jpeterman.com/ 
The last website for now is TopVintage https://topvintage.net/en/ They are also a gamble for modesty but they have a good selection so I think you will be able to find something that suits you. They have great quality and service.


Where I have bought hats: 
East Angel Harbor Hats https://www.etsy.com/shop/EastAngelHarborHats?ref=l2-shopheader-name The maker is very helpful and a good Christian. She is very pleasing to work with. I HIGHLY recommend her site.
Emily Way Hats https://www.etsy.com/shop/EmilyWayHats?ref=search_shop_redirect (Victorian style)
MargeIilane https://www.etsy.com/shop/MargeIilane (If you like to wear fascinators like Duchess Kate Middleton, this is a good place to look!)