Frontal- The frontal plane divides the body into front and back. This involves abduction and adduction exercises. (sideways movements) Exercises that take place in this plane include lateral raises, shrugs, and jumping jacks.
Transverse- The transverse plane divides the body at the waist into upper and lower body sections. This deals with rotation types of movements. Common exercises include cable wood chopping, Russian twists, and swings for tennis and golf.
Some exercises will involve different planes of motion depending on how strict one's form is and if one is doing pullups or chin up variations instead.
If we want to prevent injury and strengthen our bodies, then we should train them how they will be performing in real-life scenarios. Using multi-planar angles can help you work out in different planes of motion and give you a better rounded workout. If you are in the habit of doing only single plane exercises, then I'd encourage you to experiment with making variations to your exercises so your work out will better prepare you for real life movements and activities.