As far as most recognizable Transformers, you do not get any more visible with a character then Optimus Prime. The Red cab over Freightliner cab over engine semi-trailer truck pulling a silver trailer. Although the make, model and color scheme have changed frequently over the years the basic premise usually has stayed the same although he has been a car and a pickup truck and under the Optimus Primal name has been a bat and an ape. But this shining red, silver and blue commander is not the only prime to fight the evil Decepticons nor will he be the last. in 1984 Hasbro took the Japanese Takara Diaclone toy called “Battle Convoy” stuck Autobot symbols on his trailer and called him Optimus Prime. He would lead the Autobots and become a pop icon. As the Transformer history and even the future was explored other Primes made themselves evident and none more noticeably the Rodimus Prime. The adult version of Hot Rod, a red and yellow sports car that get a funny looking Winnebago type trailer as he takes over command from the seemingly dead Optimus. And that is just one version of what happened, the Transformer universe fractured alternate realities with differences popping up between the Cartoon series, the comic book and the animated movie. Each of these became something different in the telling and from there on other alternate realities came to be such as the live action movies. but out of all this Optimus still stands tall and is a real leader. I am now going to list all the primes that we know of in chronological order. I also note that in several of the universes that the planet Cybertron has now been established as the body of one of the biggest transformers ever known as Primus who created all the transformers from his body and the Prime name is taken from the creator. All these names come from what is called “G1 continuity family” a grouping of slightly different alternate realities that all similar.

• Prima: He was the first Transformer. Created by Primus, he was appointed the Warrior of Light and given the legendary Star Saber sword with the Matrix of Leadership in its hilt. Chosen to lead the Thirteen against their eternal enemy Unicron (another transformer the same size as Cybertron and is Primus’s brother), he and the rest of the Thirteen were made stewards of Primus’ planetary form, Cybertron. Its planetary engines carried Cybertron across space to Unicron, where they sought battle, but Prima and the Thirteen were betrayed by one of their own, a being who would be known as The Fallen.Despite this betrayal, and despite the Thirteen’s apparent demise, The Fallen and Unicron were defeated and sucked through a black hole and into another dimension.
• Prime Nova: The first to use the name Prime but as a first name unlike his predecessors who use it as a last name or rank title but has also been known as Nova Prime and became Nemesis Prime a really bad dude.
• Guardian Prime: the first commander of the Autobots and died in battle in the early days of the war against the Decepticons. He looked pretty much like Rodimus Prime.
• Zeta Prime: His stint as Autobot leader appears to have been a short-lived one, as he died before the end of the war and was succeeded by Sentinel Prime. He has a few different looks but one was similar to Optimus but in different colors of Orange and Blue.
• Sentinel Prime: first named Sentinel Major, He also looked very much like Rodimus Prime in the comics and was replaced by Optimus Prime.
• Optimus Prime: Orion Pax would become the leader we all know and love.
• Rodimus Prime: The red and yellow guy has had many names mostly shortened to just Rodimus, but also Hot Rodimus, Rodimus Major or Minor…

Other Primes beings with names that include part of prime that got thrown out or put into one alternate universe or another.

• Primon: the forgotten Prime, in one such history he was before Prima but the Matrix forgot him. also known as Alpha Prime.
• Nominus Prime: This Prime had a short reign and is another one who is not mentioned in the main list but was prime after Nova Prime.
• Primacron: A non-robotic alien scientist that in one alternate universe created Unicorn and the first transformers.

One thing to note is that Primes have a hollow compartment in their chests to contain The Autobot Matrix of Leadership (also known as the Creation Matrix or rarely, the Autobot Matrix of Power or the Matrix of Light) is an artifact of great power, traditionally carried by the leader of the Autobots. Although its appearance differs slightly from one alternate universe stream to another, it generally appears as a glowing crystal sphere encased within a hollow metal shell, with a handle on either side and is a conduit for the power of Primus, the creator-god of the Transformers, serving as a means of access to the Allspark, the “afterlife” of the Transformer race, through which it can either bestow new Transformer life, or provide its wielder with a means of communicating with the deceased leaders who have come before them.

So this is where I end this, but Optimus Prime has and will always be a central figure in Transformers no matter what alternate universe he is in or how many toys are created.