First off, a clarification. I am aware of the definitions of both, however, the following year, when I check my beds, there are more of the "two", via self-seeding. So in effect, while annuals, they "come back" every year in the manner mentioned. So here are my two suggestions:
#1: Digitalis/Foxglove
An absolutely stunning plant, many varieties, and while they are annuals, they self-seed and are back in the same spot the next year. While I am a "nutcase" in trying to plant in singular colors, i.e. seperate Red, Pink, Yellow rose beds, etc. Each fall, I put gloves on and pick seed heads off, then in the Spring, I sprinkle them wherever. Beautiful and ellegant!
#2: Hesperes/Dame Rocket
I found these in a road ditch years ago. Think "Phlox" for flower size and similarity. They come in pink, lavender, white, purple and shades in between. They are about 4 -5' high, with a fragrance exactly of lilac. Yes, they are annuals, but reseed by themselves. Some refer to them as "invasive". I can't think of a nicer "invasive" implant to have. Note: They are very easy to pull out to keep them in check. Great cut flower when cut just before full blossom bloom.