I've chosen four plants that I've added since moving here, and they would be first on my list to add if I was starting with a new garden. They have all met or exceeded expectation and have become a permanent part of the landscape.
This is the Purpleleaf Sandcherry (Prunus x cistena), I adore the colour of the foliage & there are very pretty little white/pink blooms in the spring. It isn't getting as much sun as it would like, but will get more once it's a little bigger (which would happen faster if it wasn't shaded, one of the downsides to adding new plants to a mature yard).
The False Sunflower (heliopsis helianthoides) 'summer sun' is next on my list, it is so very easy to grow and produces happy yellow blooms that are great for cutflowers. I give a bouquet and some seedlings to anyone & everyone who visits in the summer. It is planted all along the side of the house in poor clay soil in both sunny & shady spots and it shows no difference in growth habit.
The Ivory Halo Dogwood (Cornus alba 'Bailhalo') is very special to me. I planted it to remember a special canine friend. I've always been a fan of variegated leaves and this one is just beautiful. It grows quickly and does well with clay soil and is in a very shaded spot.
I always grow Blue Star petunias, they are my go to annual for the front raised planters. Even though they are sun loving, they tolerate their shady beds well, becoming a little leggy which adds to their height and visibility. Imagine disappointment the year I waited too long and they were sold out.
I would love to read about Your signature plants.