Goatsrue is in the pea family, which contains many familiar species, all of which are leguminous. Brooms (Scots, Spanish, French, etc.), lupines (many are native!), clovers and black locust are the most common and recognizable members of the pea family in the Pacific Northwest. The vetches and wild peas, some of which are native and some of which are weedy, tend to most closely resemble goatsrue.
And they’re not that close. Vetches and wild peas are viney and tend to creep along the ground or over other plants, with white, pink, or purple flowers and tendrils that twist around nearby objects for support. In contrast, goatsrue has flowers that tend towards a pale lavender (though white flowers are known) and lacks tendrils. Both goatsrue and its cousins create peapod structures (being peas, after all), though goatsrue pods tend to look a little rumpled and twisted.