Vintage items are amazing items you just can't find in your nearest high street or alternative shop, they give you an unique edge and they're actually cheaper sometimes. For example vintage bloomers are cheaper than bloomers created by someone else following a pattern or on a machine.
Bloomers and petticoats, cheap and easy to customise.
Parasols, expensive but full of detail. You'll most likely parasols that are for decoration only, this simply means they can be displayed not used. You could take them to a Craftmans to see what can arranged, it's usually just the spoke that's rusted or broken so the fabric can be removed.
Capes and capelets are a great alternative to a coat.
Waistcoats are easy to find but the most common ones are colourful and patterned ones from the seventies, you could possibly dye some of them or save your time and money for a much older waistcoat.
Chatelaines were usually designed to be attached to a belt and carried a mini version of anything a vintage woman would have needed (eg mini sewing scissors and keys) from a chain.