There are a lot of Malayalam writers who have contributed greatly to the Malayalam literature. It is not easy to answer such questions because there will be lot of subjectivity, based on a readers’ tastes, temperaments, likes and dislikes, period of time etc.
Here is my top 10 Malayalam authors:
M. T. Vasudevan Nair
Madath Thekkepaattu Vasudevan Nair popularly known as MT. He is an Indian author, screenplay writer, and film director. He is a prolific and versatile writer in modern Malayalam literature. He is one of the masters of post-Independence Indian literature. He was born on 15 July 1933 in Kudallur, Palakkad district. M. T. Vasudevan Nair is a scriptwriter and director of Malayalam films.
His debut novel Naalukettu (Ancestral Home- translated to English as The Legacy), wrote at the age of 23. He won the Kerala Sahitya Akademi Award in 1958. His other novels include Manju (Mist), Kaalam (Time), Asuravithu (The Prodigal Son – translated to English as The Demon Seed), and Randamoozham (The Second Turn). The deep emotional experiences of his early days have gone into the making of MT’s novels. Most of his works are oriented towards the basic Malayalam family structure and culture and many of them were path-breaking in the history of Malayalam literature. His three seminal novels on life in the matriarchal family in Kerala are Naalukettu, Asuravithu, and Kaalam. Randamoozham, which retells the story of the Mahabharatha from the point of view of Bhimasena, is widely credited as his masterpiece.
Vaikom Muhammad Basheer
Vaikom Muhammad Basheer is also known as Beypore Sultan. He was an Indian independence activist and writer of Malayalam literature. He was born on 21st January 1908. He was a writer, humanist, freedom fighter, novelist, and short-story writer, noted for his path-breaking, down-to-earth style of writing. This made him equally popular among literary critics as well as the common man. His notable works include Balyakalasakhi, Shabdangal, Pathummayude Aadu, Mathilukal, Ntuppuppakkoranendarnnu, Janmadinam, and Anargha Nimisham. The translations of his works into other languages have earned him worldwide acclaim. The Government of India awarded him the fourth highest civilian honor of the Padma Shri in 1982. He was also a recipient of the Sahitya Academy Fellowship, Kerala Sahitya Academy Fellowship, and the Kerala State Film Award for Best Story.
S. K. Pottekkatt
Sankaran Kutty Kunjiraman Pottekkatt is popularly known as S. K. Pottekkatt. He was an Indian writer of Malayalam literature and a politician from Kerala, India. He was born on 14 March 1913. He was also a great traveler among the Keralites, who wrote many travelogues for the people who have been unintroduced to the outside world. He was the author of nearly sixty books which include ten novels, twenty-four collections of short stories, three anthologies of poems, eighteen travelogues, four plays, a collection of essays, and a couple of books based on personal reminiscences. He was a recipient of the Kerala Sahitya Akademi Award for Novel, Sahitya Akademi Award, and the Jnanpith Award. His works have been translated into English, Italian, Russian, German, and Czech, besides all major Indian languages.
Maniyambath Mukundan is commonly known as M. Mukundan. He is an Indian writer of Malayalam literature. He was born on 10 September 1942. Many of his early works are set in Mahé (Mayyazhi) which has earned him the moniker, Mayyazhiyude Kathakaaran. He is known to be one of the pioneers of modernity in Malayalam literature and Mayyazhippuzhayude Theerangalil, Daivathinte Vikrithikal, Kesavante Vilapangal, and Pravasam are some of his notable works. He has received many honors including Vayalar Award, Sahitya Akademi Award, Kerala Sahitya Akademi Award. Crossword Book Award and the Ezhuthachan Puraskaram, the highest literacy honor of the Government of Kerala. He is also a recipient of the Chevalier des Arts et des Lettres of the Government of France.
Kamala Surayya (Madhavikutty)
Kamala Surayya popularly known by her one-time pen name Madhavikutty and married name Kamala Das. She was an Indian poet in English as well as an author in Malayalam from Kerala, India. She was born on 31 March 1934. Her popularity in Kerala is based chiefly on her short stories and autobiography, while her oeuvre in English, written under the name Kamala Das. She is noted for the poems and explicit autobiography. She was also a widely read columnist and wrote on diverse topics including women’s issues, child care, politics among others.
Thakazhi Sivasankara Pillai
Thakazhi Sivasankara Pillai popularly known as Thakazhi after his place of birth. He was an Indian novelist and short story writer of Malayalam literature. He was born on 17 April 1912. He wrote over 30 novels and novellas and over 600 short stories focusing on the lives of the oppressed classes. He was known for his works such as Kayar (Coir, 1978) and Chemmeen (Prawns, 1956), Pillai was a recipient of the Padma Bhushan, the third-highest Indian civilian award. He was also a recipient of the Jnanpith, India’s highest literary award, awarded in 1984 for the novel Kayar.
P. Kesava Pillai was better known by his pen-name P. Kesavadev. He was a novelist and social reformer of Kerala, India. He was born on 20 July 1904. He is remembered for his speeches, autobiographies, novels, dramas, short stories, and films. Odayil Ninnu, Nadhi, Bhrandalayam, Ayalkar (Central Academi Award-winning novel), Ethirppu (autobiography), and Oru Sundariyude Athmakadha are some among his 128 literary works. Kesavadev along with Thakazhi Sivasankara Pillai and Vaikom Muhammad Basheer is considered the exponents of progressive Malayalam Literature.
Sarah Joseph (born 1946) is an Indian novelist and short story writer in Malayalam. She won the Kendra Sahitya Akademi Award for her novel Aalahayude Penmakkal (Daughters of God the Father). She also received the Vayalar Award for the same novel. Sarah has been at the forefront of the feminist movement in Kerala and is the founder of Manushi (organisation of thinking women). She and Madhavikutty are considered among the leading women writers in Malayalam. She joined the Aam Aadmi Party in 2014 and contested the 2014 parliament elections from Thrissur.
O. V. Vijayan
Ottupulackal Velukkuty Vijayan commonly known as O. V. Vijayan. He was an Indian author and cartoonist. He was an important figure in modern Malayalam language literature. He was born on 2 July 1930 in Palakkad. He was best known for his first novel Khasakkinte Itihasam (1969). Vijayan was the author of six novels, nine short-story collections, and nine collections of essays, memoirs and reflections.
Lalithambika Antharjanam was an Indian author and social reformer. She was best known for her literary works in Malayalam language. She was born on March 30, 1909. She was influenced by Mahatma Gandhi and social reform movements among the Nambuthiri caste led by V. T. Bhattathiripaatu. Her writing reflects a sensitivity to the women’s role in society, in the family and as an individual. Her published oeuvre consists of nine volumes of short stories, six collections of poems, two books for children, and a novel, Agnisakshi (1976) which won the Kendra Sahitya Akademi Award and Kerala Sahitya Akademi Award in 1977. Her autobiography Aathmakadhakkoru Aamukham (An Introduction to Autobiography) is also considered a significant work in Malayalam literature.
There are many additional names across various categories, whom I consider to be worthy and quality contributors to Malayalam literature. Please mention them in the comments.