The design of the classic overcoat has really changed very little in the last century or so - good news for vintage wearers since original vintage overcoats are generally rare and pricey. My own overcoat - from Marks & Spencer two years ago - is almost identical in design to style E from 1942.
There are two basic silhouettes: fitted and boxy.
Fitted reefer and boxy swagger coats, 1942
Wide sleeves in 1952
Princess coat and swagger both gain volume by the mid-fifties (above, 1956)
Jackets & Topper Coats
Tailored jackets in wool plaid, tweed or flannel or short boxy swing jackets for 1930s-40s smart-casual:
Surpsingly modern-looking styles in the 1950s: Duffel coat, mid-length belted jacket, zip-front jacket and the classic plaid 49er.
After spending last winter scouring ebay and etsy (without success) for an affordable wool cape, one practically fell in my lap last week. Hot pink, probably 1960s, all wool, and £5 (due to scattered moth nibbles): win.
Originator 299 sewing pattern, early 50s
Vogue Couturier Design 1120 sewing pattern, circa early 60s
Fur & Faux Fur
Controversial, yes, but there's no denying it is warm. I should point out that I'm 100% anti new fur (not just because I object to animals being farmed and killed - I do eat meat - but mostly because of their welfare while they're alive). But I don't have a problem with vintage fur: I'd rather it be worn than be tossed out and end up on the scrap heap and in landfill - to me that shows less respect for the animal than wearing it and appreciating it, as well as being ecologically unsound (if you consider the environmental cost of manufacturing new faux fur to replace the vintage fur you just threw out). Of course, vintage faux fur is a cosy alternative to real, with none of the controversy.