With the right combination of specs and/or a distinctive look, a special edition can turn a fairly ordinary car into a highly sought-after collector's item. Special editions aren't always remembered, though. There have been plenty of special edition cars that have ended up just being footnotes or odd curiosities in automotive history. Sometimes it's because they were barely any different from the more standard variants. Other times, it was because they appealed to a really small niche. Then again, some were just downright bizarre.What's different about the sedans on this list is that they're all incredibly rare and mostly forgotten by gearheads. They're models anyone could stumble onto when browsing the used car market or even hidden away in a barn somewhere. Most people can't tell them apart from regular models, but their rarity makes them incredibly cool and potentially valuable -- but only among those who know they exist. Read this list, and you'll be one of those people. Lincoln Town Car Jack Nicklaus Signature Series AuroraTerra, via Wikimedia CommonsWhen it comes to classic American luxury, you can't do much better than the Lincoln Town Car. The second generation of the Town Car, built between 1990-1997, is perhaps one of the best examples of that. It's got that classic boxy American sedan styling, and its internals are still fairly old-school even for the '90s. The only concession to modernity is the 4.6-liter Modular V8 that was introduced after 1991.While most versions of the second-generation Lincoln Town Car weren't that weird, there's one special edition of it that's a bit of a headscratcher. That model is the Jack Nicklaus Signature Series, which was available from 1992-1997. Named after the famous golfer, this version of the Town Car was usually green with a white vinyl top or white with a green vinyl top. The interior followed the same color scheme. Many of them also had gold trim on the outside, and some had the vinyl top deleted as an option.It's very rare that you see a special edition car named after a famous person. There's probably a good reason for that. Naming a special edition sedan after Jack Nicklaus must have seemed bewildering to people back in the '90s, let alone today! The Lincoln Town Car Jack Nicklaus Signature Series has faded into obscurity now. Only a real Town Car enthusiast (or a real golf enthusiast!) will remember these, or know what one of them is. Rolls-Royce Ghost Majestic Horse Edition Why was this special edition Rolls-Royce sedan forgotten? It's probably because of how bizarre it was. This was a car that was designed for fairly specific buyers. Rolls-Royce wasn't expecting most of its clients to want something as ostentatious as the Ghost Majestic Horse Edition. So, most people would have thought it was just too crazy for them and ignored it from then on. Lexus LS400 Coach Edition LexusLexus isn't typically known for making special edition cars. That makes a lot of sense. Lexus is a very understated brand, loved by those who like to keep their wealth a bit more hidden. They're not flashy, and they're much more about comfort and solid engineering than anything else. That's something reflected in this special edition of the Lexus LS400. The Coach Edition was only made for the 1997 model year. It was a collaboration with the Coach leather goods company, and it's barely any different from the standard LS400. The only way you'd be able to tell a Coach Edition is a Coach Edition is through some exterior and interior details. These include unique wheels, different badging, unique leather upholstery made by the Coach company itself, the Coach logo being present in the interior and a wood and leather-accented shift knob for the 4-speed automatic transmission.Proper Lexus enthusiasts actively seek out Coach Edition LS400s. But, to the vast majority of people, it's so similar to the standard car that they'll have forgotten about it very quickly. Lexus ES300 Coach Edition Bring A TrailerThe Lexus LS400 wasn't the only car that got the Coach Edition treatment. The ES300 got that treatment too! The Lexus ES300 Coach Edition appeared in 1996, a year earlier than the LS400 Coach Edition. The ES300 Coach Edition came with similar Coach-themed additions to the LS400 Coach Edition. It also came with a custom Coach bag.Like the Lexus LS400 Coach Edition, the ES300 Coach Edition is barely any different from the regular model. It's mechanically the same as the regular ES300, and it barely looks any different from a regular ES300 either. As a result, it wouldn't have stuck in the minds of anyone except die-hard Lexus enthusiasts. Oldsmobile Alero Final 500 Edition State Line Auto AuctionWhen the 2000s came around, General Motors had a lot of financial problems. It needed to streamline things fast, or it wouldn't exist as a company anymore. One of the more controversial decisions GM made during this time was to get rid of the Oldsmobile brand. As part of Oldsmobile's winding up, General Motors decided to produce Final 500 versions of all the remaining Oldsmobile models. The Final 500 edition variants were all mechanically similar to the standard variants. The big difference was cosmetic. They had the same distinctive color scheme inside and out (a dark cherry-colored exterior with a cream-colored interior), unique badging inspired by Oldsmobile badging from the good old days of the brand, and a plate that showed the car's number out of the final 500.The FInal 500 edition models included 3 sedans, and all of them are going to be featured on this list. The first of those is the Oldsmobile Alero. This is a compact car that was introduced for the 1999 model year, and shared a lot of components with the Pontiac Grand Am of the same era. The Alero Final 500 edition only had one engine option, the top-of-the-range 3.4-liter V6 that produced 170 hp and 200 lb-ft of torque. The last of the final 500 Aleros was also the final Oldsmobile ever produced, rolling off the production line on April 29, 2004. This example wasn't sold to the general public. Instead, it was given to the R.E. Olds Transportation Museum, where it stayed until 2017. The Museum put it up for auction, and it was sold on December 15 to a dealer in Florida. Its new owner reportedly paid $42,000 for it.While the cosmetic differences do make it look cooler than the regular Oldsmobile Alero, it's still a fairly mediocre early 2000s GM sedan. As a result, most people have forgotten about this end-of-the-line special edition. Only the proper Oldsmobile enthusiasts (like that Florida dealer likely was) know about these and how important they actually are. Oldsmobile Aurora Final 500 Edition Mecum AuctionsThe second of the 3 Final 500 Edition sedans, the second-generation Oldsmobile Aurora first appeared in 2001. Sharing components with the Buick LeSabre, Buick Park Avenue, Pontiac Bonneville, Cadillac DeVille, and Cadillac Seville, this was a more upmarket model that had more powerful engines and a more luxurious interior. The Final 500 Edition version of the Aurora was only available with the Northstar V8 engine, producing 250 hp and 260 lb-ft of torque.Out of the Final 500 Edition Oldsmobile sedans you can get, the Aurora is probably the best one. Even so, the Northstar V8 doesn't have the greatest reliability record as an engine. Like the other Final 500 Oldsmobiles, it's also pretty boringly normal apart from the cosmetic differences. It's no wonder that this special edition sedan has been mostly forgotten. Oldsmobile Intrigue Final 500 Edition The 3rd and last of the Final 500 Edition sedans, the Oldsmobile Intrigue was a car that should have saved the ailing brand. It was a mid-sized model that slotted between the Alero and the Aurora, intended to compete with other mid-sized sedans from Europe and Japan. But, it failed at trying to compete with the more reliable and better quality Acuras and BMWs that North American customers could buy in the '90s and '00s.Like the other Oldsmobile models on this list, it shares parts with several other GM models of the day. That includes the Buick Century, Buick Regal, Chevrolet Impala, and Pontiac Grand Prix.The Oldsmobile Intrigue Final 500 Edition has been forgotten in the same way as the other Final 500 Edition Oldsmobile sedans have been. Apart from the special cosmetic changes, they're just fairly normal GM sedans of the era. As a result, they're not really that memorable. People usually preferred the Intrigue's'European and Japanese rivals, and those cars are remembered a lot more than one of a dying brand's final gasps. Rolls-Royce Ghost Golden Sun Bird Rolls Royce Ghost Golden SunbirdAnother crazy special edition Series I Rolls-Royce Ghost, the Ghost Golden Sun Bird is another incredibly luxurious car catered to Chinese customers. Specifically, it was a one-off commission for an unnamed Chinese client. It was inspired by and named after an artifact from the Shang Dynasty. The influence from the original Golden Sun Bird artifact is shown in the car, having gold all over it. The inside and outside of the car have gold panels and accents everywhere, including a two-tone gold and white paint job and gold embroidery. The original Golden Sun design is also embroidered into the seatbacks and sill plates.You'd think that people would remember the Ghost Golden Sun Bird, considering it was a mad one-off commission that did get a proper press release and photoshoot. But, people have mostly forgotten it. Perhaps it's been forgotten for the same reason the Ghost Majestic Horse Edition was. It's simply too weird for the tastes of anyone who isn't part of the specific market Rolls-Royce was making it for. Rolls-Royce Phantom Coupe Aviator The Rolls-Royce Phantom Coupe is a car that's rare enough as it is. The Rolls-Royce Phantom Coupe Aviator is a whole different level of rare! Only 35 of these were ever built, and they were intended to celebrate the company's aviation heritage. Specifically, it's a tribute to the Supermarine S.6B Seaplane that won the Schneider Trophy in 1931. A Rolls-Royce engine powered this plane, so it's definitely fitting that Rolls-Royce would want to pay tribute to it! The Phantom Coupe Aviator is all silver on the outside, paying homage to the Supermarine S.6B's original color. It also has aviation-themed details on the inside. This includes an aviation-grade clock, much like something you would find in a plane from the early 20th century.The Rolls-Royce Phantom Coupe Aviator is possibly one of the most beautiful and tasteful special edition Rolls-Royces. But, the Phantom Coupe as a whole is a car that's barely talked about anymore. Being a rarity within a rarity, the Phantom Coupe Aviator is a car that was bound to end up just being a footnote in Rolls-Royce's history. Rolls-Royce Phantom Celestial Rolls-RoyceThe final special Rolls-Royce sedan on this list is another one based on the Phantom. This is the Rolls-Royce Phantom Celestial, and it's another car that was built to celebrate a part of Rolls-Royce's history. That was the time when the first Phantom rolled off the production line. The starlight headliner has been set to the position of the stars on January 1, 2003, and the starlight theme doesn't end there. The paint is a special shade that has fine particles of glass in it to mimic stars in the night sky, and it has a special "dusk" interior to fit in with the night-themed colors. There's celestial-themed glassware in the car, and a lot of diamonds were used in making the interior.This was supposed to be one of the most exclusive cars Rolls-Royce has ever made, and represent a really important part of its history. Sadly, though, most people seem to have forgotten about it. That's a bit of a shame, because it is a genuinely beautiful example of a Phantom. At least die-hard Rolls-Royce enthusiasts will appreciate it as it should be.