If you are looking for an isolation exercise for your triceps, I highly recommend One-Arm Dumbbell Tricep Extension.
Steps:

Hold dumbbell in right hand and raise overhead to arm’s length.
Stand straight up, with your head up and feet at shoulder width. Keep upper arm close to your head.
Lower dumbbell in a semicircular motion behind your head [...]

Triceps dip is a compound exercise which triceps are the main muscle involved in addition to chest and shoulders. Dips work all three heads of the triceps muscles at once. The triceps brachii has three heads: the lateral, medial, and long heads.
Often called the “upper body squat,” dips are highly recommended for any [...]

Lying Triceps Press is an isolation exercise which triceps are worked out. It is probably the best exercise to build size and strength, particularly the large inner head of the triceps muscle. I like the lying tricep extension and I have always performed it as the first exercise for my triceps workouts.
Steps:

Sit on [...]