In this patch, I'm working towards a mix of violets (Viola sororia), nimblewill (Muhlenbergia schreberi), white avens (Geum canadense), and yellow woodsorrel (Oxalis stricta). There's also clover, chickweed, mock strawberry and others I'm weeding out. The shrub is an elderberry (Sambucus canadensis) which should get 10 feet wide. The top right corner is a mix of Philadelphia fleabane (Erigeron philadelphicus) and orange coneflower (Rudbeckia fulgida).
This is an urban area in the North American Eastern Temperate Forests. My yard is the lowest point of the street next to the storm drain, a "rain garden" for the block. Here, the violets thrive from deep shade to full sun. They are the host plant for fritillary butterflies.
I never took care of the lawn other than mowing it, so much of this stuff was already here in small amounts. Two years ago, I started dividing up the violets and planting them into the grass. They launch seeds up to 4 feet so they quickly spread, clump and bully the grass. Ants move the seeds around too. Last year, I started dividing and transplanting the nimblewill. Panicled aster and late boneset volunteered which pushed out some more.
There's still plenty of grass closer to my neighbor who treats their lawn. Some I buried in woodchips, the rest I'd like to shade out with edibles and dig out for another rain garden.
Thanks for answering! It looks great!