Resistance bands and tubing:

Rubber bands and tubes provide opportunities for strength training any time and any place. Bands are flat and wide. Tubes are round and were initially used by doctors in surgery. Cheap, lightweight, and portable bands and tubes are the training tool of choice for frequent travelers. Latex-free versions are available for people with allergies.While not strictly in the category of resistance training equipment, the following tools provide means to enhance your weight training programs.

Balls and foam rollers: 

Add balls and foam rollers into many exercises to provide an unstable surface on which to work. Incorporating this element of instability increases the difficulty of the exercise by requiring the use of deeper abdominal and back muscles

Body weight:

Your body may not feel like a training tool, but use your own body weight to provide effective resistance in a number of exercises such as the squat and lunge

Yoga and Pilates: 

Yoga and Pilates aren’t styles of weight training; however, many yoga and Pilates moves involve challenges that strengthen muscles. The particular advantage of many of these exercises is that they also involve flexibility and encourage the development of strength, balance, and coordination through movement patterns