I saw this gorgeous mix of annuals in Töölönlahdenpuisto park in Helsinki last summer. Would love to try and recreate something similar in my garden sometime. They even provided the full planting scheme for the entire park.
In this photo you can mostly see: callistephus chinensis ’matsumoto apricot’, hordeum jubatum, tagetes tenuifolia ’lulu’ and scabiosa atropurpurea ’oxford blue’ with sunflowers and nicotiana in the background.