"Superstar" Billy Graham is the direct influence of Hulk Hogan, Scott Steiner, and Jesse Ventura in image and mannerisms, which all three have alluded to in the past (Hogan in shoot interviews, Steiner by briefly using the name "Superstar", and Ventura by claiming Graham copied him!)
"Nature Boy" Ric Flair was an expy of "Nature Boy" Buddy Rogers
Flair would later get an expy of his own in "Nature Boy" Buddy Landel
The Rock N Roll Express (Ricky Morton and Robert Gibson) perfected the underdog heartthrob pretty boy babyface team role in the 1980s and spawned several expies, most notably the Rockers (Shawn Michaels and Marty Jannetty) and, later, the Hardy Boyz (Matt and Jeff.)
The Great Kabuki spawned several expies, some of whom spawned expies of their own.
The first was Kendo Nagasaki, who was followed by the Great Muta, Kwang the Ninja (Savio Vega in a mask), "The Japanese Buzzsaw" Yoshihiro Tajiri (who used the mist but not the face paint) and "Tokyo Monster" Kahagas.
TNA's Kiyoshi is an expy of Muta as well. Of course, some might say that TNA is an expy of WCW altogether.
What do you get when you cross the promotion dominating goals of the nWo with the youth of the Natural Born Thrillers? The Nexus.
WWE and TNA have been having a little game of back and forth with the same types of characters. Granted, they're common tropes, but one tends to pop up a few weeks or months after the other, making it look more like a blatant combo of expy and Follow the Leader. Some Examples:
And TNA is doing expy versions of much older WWE characters. Orlando Jordan's playing with gay stereotypes bears a few similarities to Goldust. Mr. Anderson is the same type of loudmouth as The Miz (who is an expy of Anderson back when he was Kennedy.)
Orlando Jordan is actually bisexual in real life.
Alberto Del Rio and John Bradshaw Layfield are both expies of Ted DiBiase, in so far as being richer-than-thou characters who flaunt it in the face of the audience (given that a recession is always either around the corner or already in full swing, this always gets heat).
Jack Swagger is basically a whinier, lamer Kurt Angle - both are formers amateur wrestlers that use the Ankle Lock as a finishing move, dress in the traditional singlet and are very very proud of their amateur acomplishments.
Not to mention the usage of American patriotism in their gimmicks.
YMMV, obviously, but most people seem to see Orton as "Stone Cold without the charisma". While in mid-late 2011, CM Punk seems to be doing a much better job with the "anti-establishment, badass, acts-like-a-heel anti-face" character that Austin played.
Mason Ryan will get "Batista!" chants in some of the smarkier cities he wrestles in.
The Road Warriors were a huge smash hit in the 1980s, changing tag team wrestling forever. The various companies couldn't rip off their gimmick (that being "huge tough guys who smashed-up everyone and didn't care who they beat on") fast enough. The Powers of Pain were formed to feud with the Warriors, and the WWF threw a couple of solid midcard performers together creating Demolition. All of these teams ended up feuding with each other at various times.
The Road Warriors themselves made an expy of their own named Power Warrior (Kensuke Sasaki) in Japan, who formed the Hell Raisers with Hawk when Animal was injured and later formed the Hell Warriors with Animal when Hawk passed away.
For a period during 2010 and 2011, WWE tried turning Michael Cole into a new version of Vince McMahon's "Mr. McMahon" character. Unfortunately, it failed spectacularly, mostly because McMahon actually was the boss of WW(F/E), while Michael Cole was simply an announcer. Thankfully, WWE ended the experiment at Over The Limit 2011, with Cole returning to his neutral Chew Toy announcer role on Raw the night after — though he does still show a tendency to root for the heels.
The Renegade defeated Arn Anderson for the WCW World Television Title at the Great American Bash in June 1995 and lost it to Diamond Dallas Page that September. He never got another push, being reduced to Jobber status. The man who Hulk Hogan had said would take "Hulkamania into the 21st Century" never got to see it. WCW released him in late 1998 and he committed suicide on February 23, 1999 at the age of 33.
Beer Money Incorporated is an expy of the Acolyte Protection Agency, they even have the same manager.
Dave McLane will use similar character type repeatedly in his various promotions GLOW, POWW, and WOW.
CM Punk's current heel turn makes him an expy of Harley Race in the way of stating himself as the very best and how people MUST admit that they respect him. This is very similar to Race's heel run as "King" Harley Race where he told his opponents and detractors to bow and kneel before him. Whereas Race had Bobby Heenan, Punk has Paul Heyman. Punk even goes as far as trimming his beard much like how Race's looked and wearing colors matching Race's at the time.