I also made quite a few using just purple and pink. The purples are clustered bellflowers and another bellflower I only know as 'Kent Belle'. It may be some kind of hybrid, I don't know. The pinks include delphinium, phlox, astilbe and clarkia.
Also did a few apricot and purple like this one using apricot lilies with the same purple bellflowers plus achillea 'Terra Cotta'
About half a dozen bouquets were blue and yellow. Most of my heliopsis died over the winter so I won't have many. I started more this year but I should have done it last year. You can also see a yellow centaurea, white annual gypsophila and yarrows.
I almost never make anything containing only two kinds of flowers, but I made quite a few bouquets containing only delphiniums and clarkia - basically salmon and blue.