This is a great exercise that improves shoulder health and promotes optimal posture. It helps to strengthen shoulder and upper back muscles that are often weak and under-trained, and it helps to remind you of upright posture and proper thoracic spine extension. It is also the best cure for chronic "texting posture". I recommend purchasing a light resistance band and performing this exercise daily whenever you have the chance. Bring it to work or set it in a common area in your home. Do it multiple times per day and keep the repetitions high (12+) per set.
This is like the pull apart for your hips. It trains muscles that provide stability in a plane of movement that we rarely move in(unless you are an athlete). It works primarily the smaller gluteal muscles that control excessive movement of the hips and lumbar spine and gives you more stability during single leg movements (such as walking or climbing stairs). This exercise can be done with just your bodyweight(side-lying) or you can use a resistance band to train the muscles in a standing position.
You can also perform the exercise from a modified side plank position to increase the challenge to both the hip and core muscles.
One last option is to perform this movement standing with a resistance band.
This is another great exercise that trains your body in a plane of movement that we don't often use. The goal of this exercise is to remain rigid and stable to prevent rotation of the spine. If done correctly, with adequate resistance and proper tension, this turns into a full body exercise. You can feel it working from your shoulders, to your glutes, and everywhere in between.
This is another great shoulder and postural exercise. It is great for training shoulder retraction and upward rotation for the shoulder blade, both of which are important for long term shoulder health. This one is more of a "motor control" movement so I do not usually add resistance to it. I focus more on the quality of the movement and try to feel all the muscles of the back and shoulders working. This is a great exercise to perform during a warm up to help mobilize and activate the back/shoulders before higher intensity movements.
So there are four exercises that I highly recommend regardless of overall training goals. These exercises help to promote optimal movement, decrease risk of injuries, and require minimal equipment. You can perform all of these movements as part of your general warm up or just "sprinkle" them into your routine throughout the week. I believe that performing these exercises, along with the basic compound movements previously mentioned, you can keep your body moving and feeling good for a long time.