In your own expertise, what triceps exercise most helped you produce a huge longhead?

[ChangeOfStyle]

Lateral triceps head right now seems pretty decent, however the long head really gives that visualization of a huge arm. What exercise best builds it?

Just to give a simple idea of my routine, it alternates every 2 weeks in my push regime with;

Superset of

Triceps pushdown with Bar
+
Triceps pushdown with Rope

Superset of

Standing Skullcrushers
+
Standing Triceps Dumbell Overhead

[Garage Rat]

Anything that gives a good stretch to the triceps.
Overhead bent over behind the head cable extensions.
Oldschool pullover and presses or even a ez bar tricep extension letting the elbows come back and then up each rep.
Your basically stretching them and then a contraction.
The standing on arm DB extensions are good as you mentioned.

[WeightedDip]

Lateral triceps head right now seems pretty decent, however the long head really gives that visualization of a huge arm. What exercise best builds it?

Just to give a simple idea of my routine, it alternates every 2 weeks in my push regime with;

Superset of

Triceps pushdown with Bar
+
Triceps pushdown with Rope

Superset of

Standing Skullcrushers
+
Standing Triceps Dumbell Overhead

The moves that allow you to push the most weight. Weighted Dips and Close Grip Bench. Call it beginner gains, but I added 2" to my arms in a year and a half. Two of my biggest exercises over that year and a half were weighted dips / weighted pull ups and chin ups.