1) Rajiv Menon
Though primarily a cinematographer, Rajiv Menon has so far directed two films, Minsara Kanavu (1997) and Kandukondain Kandukondain (2000). Both films were critically and commercially successful, with his directorial debut receiving four National Film Awards. His second film earned him the Filmfare Award for Best Tamil Director and Filmfare Award for Best Tamil Film. Another Menon, Gautham Menon also worked as Rajiv's assistant director before directing his own movies. Rajiv is still going strong as a cinematographer though he is yet to return to script-writing and directing.
2) Kathir
Before there was Gautham Menon and Selvaraghavan, there was Kathir who came closest to rivaling Mani Ratnam in the genre of romance. He is the man who gave us Kadhal Desam (1996) and Kadhalar Dhinam (1999). He often collaborates with AR Rahman, who has given us some of his best tunes during the 90s when collaborating with Kathir. He was supposed to make a comeback with either Srikanth or Shaam but there has been no word on this new project.
3) Santosh Sivan
Another cinematographer turned director, Santosh Sivan focuses more on his first career then his second, despite having directed some of the most daring and critically acclaimed Tamil films in recent times. His films mostly fall into the alternative cinema category, which is probably why they are more famous for making rounds at international film festivals instead of making money at the box office. Four of his ten directorials are in Tamil, all of them featuring female main characters like The Terrorist (1997), Malli (1998), Navarasa (2005) and Ceylon (2013).
4) Priyadharshan
Yes, he is more popular now as the director who remakes his own and others' Malayalam blockbusters for Bollywood. He also rarely works in Tamil cinema, although he has given us some of the most critically acclaimed and daringly unique Tamil films in recent years. He made his debut in Tamil cinema with Gopura Vasalile (1991), one of the earliest Tamil-language black comedies. Then, he made films featuring female lead characters with Snegithiye (2000) and Lesa Lesa (2003), which is very rare in Tamil cinema these days. His most recent Tamil film is the National Award-winning historical drama, Kachivaram (2008) which also earned him the Best Director Award at the Filmfare Awards. He is yet to make another Tamil film.
5) Siddique
This Malayalam filmmaker has only made five Tamil films, all of them remakes of his own Malayalam blockbusters. His films are always commercial masala flicks but not the no-brainer type. Three of them have become both critical and commercial family entertainers that are famous for boosting their main leads' careers. Engal Anna (2004) and Kaavalan (2011) provided Vijaykanth and Vijay with their much needed comebacks, while Friends (2001) helped make Surya the movie star he is today. Siddique continues to be more active in Malayalam cinema as there is no word on his next Tamil-language venture.