One of the American Red Cross buttons on the left, obviously, and the British Red Cross Society ones. I think I'll use them for a more daytime-friendly version of the panzer dress - not the colour scheme, just the double-breasted cut with very wide lapels and separate collar. That kind of cut really calls for oversized buttons like these, and with that huge collar you can't see the buttons on the shoulder straps properly anyway, so I could use all six of them for the front closure. I'm very happy with that dress (even more so since I added some silver braid to it for the second time I wore it), so I would like to re-use the pattern for something else.
The jury is still out on colour, fabric and so on, but I'm tempted to go for grey cotton twill - I saw this lovely, warm grey one at NK when I bought the fabrics for my New Year's Eve dress. With my luck they're probably sold out of it by now, and it was ludicrously expensive for cotton twill, but on the other hand it's NK, which means that it will add up bonus points in their very generous customer bonus system anyway... I will look around a little, and think some more.
I have another batch of vintage buttons on their way too - faceted chartreuse glass this time, hopefully arriving some time this week. Browsing buttons on Ebay is an expensive pastime, it seems..