Native plants adapted to your region are the lowest-maintenance choice you can make, since they already handle your rainfall, soil, and winters without much help. Beyond natives, some plants earn their easy reputation almost everywhere.
For shrubs: juniper, panicle hydrangea, spirea, and boxwood. For perennials: daylilies, coneflowers, sedum, hostas in shade, and ornamental grasses like feather reed or fountain grass, which look good most of the year on one spring cutback. For ground cover: creeping thyme in sun, or vinca minor where it is not considered invasive in your area (worth checking, since it spreads).
The bigger lever than any single plant is design: group plants with similar water needs, mulch the beds, and match every plant to your hardiness zone so nothing needs babying. OutdoorBrite builds low-maintenance planting concepts on a photo of your own yard, with plant choices matched to your climate.