The Flash has some of the best villains in the DC universe. His rogues gallery have personalities that are very distinct and interesting when put next to the Scarlet Speedster. I am very happy that you guys chose this category because interesting characters call for interesting choices.
If you missed my last fan cast (being Teen Titans) you can find it here. These choices are meant to be possible in the current DCCU. I have not repeated any actors across all of my articles. I chose actors that have never played their assigned characters in live-action before. Onto my choice. First up we have:
Professor Zoom or Eobard Thawne first debuted in The Flast #139 in 1963. I chose Professor Zoom since I believe Ezra Miller will play Barry Allen in the DCCU. Thawne has proved to be one of the Flash's primary villains and is someone I expect to see in the cinematic universe. He is currently being portrayed by Tom Cavanagh in the hit TV show 'The Flash'.
Zachary Quinto is a terrific actor as seen in the current 'Star Trek' franchise. If you are unconvinced that he can play a villain then watch the first season of 'Heroes'. Quinto portrays the cold and purely evil Sylar who's evil nature is not unlike the one of Thawne. This is one casting I'd love to see come true.
Captain Cold or Leonard Snark first appeared in Showcase #8 in 1957. Cold is easily my favourite Flash villain. His moral code gives him another layer to his character adding depth to a boring robber that freezes people. He is usually the leader of the Rogues and is currently being portrayed by Wentworth Miller in 'The Flash' TV show.
Damian Lewis is most well known for his role in 'Homeland' where he plays a war veteran who comes home after being held captive for 8 years. Lewis is a great actor who can definitely bring the depth of the character. Cold is known for his challenges with his moral code and Lewis could bring in his own version of the character to portray that.
Heat Wave or Mick Rory first appeared in Flash #140 in 1963. A pyromaniac, Heat Wave is a recurring member of the Rogues often getting into 'heated' arguments with his leader, Captain Cold. His relationship with Cold is something that defines both of their characters. Heat Wave is currently being portrayed by Dominic Purcell in 'The Flash' TV show.
Logan Marshall-Green is a lesser known actor but has shown up in movies such as 'Prometheus'. He was one of the better parts of that movie and he showed that he can act. He showed an intensity and believability in his performance that could easily be transferred into Heat Wave.
Mirror Master or Sam Scudder and later Evan McCulloch first appeared in Flash #105. Mirror Master can travel through what's known as the Mirror World. He can also do other tricks using mirrors such as create holograms and physical transformations. Mirror Master has been portrayed in many different animated mediums such as TV and movies.
Dominic Monaghan is most known for his roles in 'Lost' and 'The Lord of the Rings' franchise. He is an amazing actor and could easily pull off the character of Mirror Master. His slight European accent means he could pull of either the Sam Scudder or Evan McCulloch verison of the character.
Weather Wizard or Mark Mardon was first introduced in The Flash #110 in 1959. In the New 52, he is Marco Mardon who is basically the same character but Latino. Weather Wizard uses his weather wand to control the (yep, you guessed it) weather. He is currently being played by Liam McIntyre in 'The Flash' TV show.
Diego Luna isn't known for being in many things and I have personally not seen any of his work. I chose him purely on his looks as there aren't many Latino actors with this particular look. I decided that since Weather Wizard isn't an A-list super villain, he should be played by a relatively unknown actor.
The trickster (Jesse James and eventually Axel Walker) first appeared in Flash #113 in 1960. In the New 52, the Trickster mantle is taken up by Axel Walker. The Trickster uses gadgets to pull off his missions and is a current member of the Rogues. Axel Walker is currently being portrayed by Devon Graye in 'The Flash' TV series.
You might recognise Ben Foster as Angel from the third X-Men movie but since then he has made a name for himself through indie flicks and other dramatic roles. He has grown to be quite the actor and playing a role like Trickster would definitely be something he would be interested in. There is no doubt that Foster could pull off an amazing Trickster.
Gorilla Grodd first appeared in The Flash #106 in 1959. This intellectual ape has been a major thorn in the side of the Flash and the rest of the Justice League. He has been portrayed many times in animations and video games. He has a minor role in the current 'The Flash' TV series.
Powers Boothe is most known for his work in the 'Sin City' franchise as Senator Roark. This villainous turn shows how affective Boothe can be at playing a villain. Further proving my point, Boothe has voiced Grodd in the 'Justice League' animated series.
Shade or Richard Swift first appeared in Flash Comics #33 in 1942. This dark villain has the ability to control shadows and create constructs out of shadows among other things. He has shown up in the 'Justice League' animated shows appearing as a member of several incarnations of the Injustice League.
Julian Richings isn't known for being in very much but might be recognised by the younger generation as Death for CW's 'Supernatural'. He has the look to play the character and since his role in 'Man of Steel' was virtually unnoticed, he should be able to play the part of Shade.
Pied Piper or Hartley Rathaway was first introduced in The Flash #106 in 1959. Rathaway was born deaf and used hearing implants to hear. He was fascinated by sound and eventually created a device that gave out deadly vibrations that could hypnotise people. He is currently being portrayed by Andy Mientus in 'The Flash' TV show.
Neil Patrick Harris
Neil Patrick Harris is known for his "legendary" performance in 'How I Met Your Mother'. I originally had him casted as the Trickster but I found that this role "suited" him better. (Okay crappy puns aside) Harris is a great actor as evidenced by 'Gone Girl' and his real life personality can be toyed with to create a menacing Pied Piper.
Golden Glider or Lisa Snart debuted in Flash #250 in 1977. The sister of Captain Cold, Lisa has the power of flight, ribbon-like tendrils and superhuman speed in the New 52. She is a current member of the Rogues and is currently being portrayed by Peyton List in the current 'The Flash' TV series.
Alexis Bledel is known for her starring role in 'Gilmore Girls'. She is a talented actress which shows in her small but important role in 'Sin City'. Her short appearance proved she can be manipulative and almost evil. I think she could turn in a really interesting performance as Golden Glider.
Black Flash first appeared in The Flash #138 in 1998. Black Flash is essentially death but for those who have super speed in the DC universe. It is pretty much unknown if the Black Flash even exists because Death can't catch the speedsters or as a side-effect of the speed force.
Lance Reddick is most well known for his roles in TV shows. I know close to nothing about him but he would only show up for a short while and provide almost no dialogue so I chose someone who looks the part. He could definitely pull off the small but important role with little difficulty.
I hope you liked my choices for Flash's villains. I realise I am a little late but I had other things on and had no time to complete this article. Please tell me if you liked my choices and who you want to see be casted next.