Here are some effective workouts for building more extensive and more muscular legs:

1. Squats: Squats are a compound movement that works multiple leg muscles, such as the quadriceps, hamstrings, and glutes, all at the same time. They can be done with a barbell, dumbbell, or body weight.
2. Leg press: The leg press exercise on the machine is excellent for targeting the quadriceps, hamstrings, and glutes simultaneously.
3. Lunges: Lunges are a fantastic exercise to strengthen the quadriceps, hamstrings, and glutes. It can be performed using dumbbells or only using body weight.
4. Step-ups: Step-ups target the quadriceps, hamstrings, and glutes. They can be done with dumbbells or body weight; you only need a step or bench.
5. Deadlifts: Deadlifts are multi-joint movements that focus on developing the hamstrings, glutes, and lower back. This can be executed with a barbell or with a dumbbell.

It's essential to begin with a weight that matches your present fitness level and progressively increases as your strength increases. Utilizing the correct form is also vital in preventing injuries and maximizing the effectiveness of your workout.