There are lot of exercises out there, but here are the only ones you need to be fit.
Human movement can be reduced to three basic categories: pushing, pulling, and hip extension (squatting, jumping, running, and even riding a bike).
Functional fitness begins with learning good form for this essential repertoire and then gradually adding weight and difficulty to build stability and strength.
Doing these exercises correctly with at least five pounds, in other words, is better than doing them poorly with 100.
In the words of Gray Cook, one of the founding fathers of functional training, "Don't add strength to dysfunction."
Push-ups- activate a chain of muscles, particularly in your arms, shoulders, chest, and back, that are key for everything from getting up off the ground to shoving something heavy. The humble push-up beats the bench press for developing this functional push strength because the push-up doesn't take your back and legs out of the movement. Start in a plank position, holding the spine neutral, no sagging. Stabilize the shoulder joints by pulling shoulder blades down toward your heels (this is fundamental to all push-and-pull exercises). Place hands so that when you drop, your nipples line up with the base of your palms. Lower until your chest touches the ground.
Squats- For the most elemental of human movements, sitting down and getting back up, or lifting something heavy off the ground, there is no better exercise than the squat. But form is incredibly important for preventing injury, so start with unweighted "air squats" to develop a full range of motion before adding weight. Stand with feet wider than shoulder width, toes splayed 30 degrees, your chest up and butt back. Weight should be on your heels, not your toes. Squat by pushing your butt backward, not by bending your knees forward. Knees should track directly over the feet, never caving inward or outward. Bring your thighs parallel to the floor while keeping your weight on your heels and your spine straight and solid. An advanced move is the Back Squat- once you can hold good form through 20 body-weight squats, add weight by resting an empty barbell on your back, and then add plates as you progress.
Walking Lunge- The most surprising functional-training advance of the past 15 years is the understanding that knee pain nearly always begins with weak hips, specifically, the stabilizer muscles aligning the upper leg, from the hip down into the knee. Walking lunges, a kind of exaggerated striding motion, build solid leg joints for everything from the deep knee bends of powder skiing to walking up a flight of stairs. For the walking lunge, simply take one big step forward, plant your foot, and bend your forward knee 90 degrees while bringing the rear knee low enough to almost touch the floor. Repeat with the other foot. Plant your lead foot far enough forward that, as you lower into each lunge, your shin bone remains nearly perpendicular to the floor and the kneecap never extends over your foot. Do not rock back and forth with your upper body. Instead, remain perfectly upright with good posture, using abdominal muscles to keep your spine neutral. An advanced move is the Weighted lunge: Add weight to each hand at your side while lunging.
The above are some of the only moves you need to stay fit.