These are some of the online dictionaries I have found useful in my work as well as my own Kota dictionary, in progress:
Hindi and Urdu
Platts, John T. (John Thompson). A dictionary of Urdu, classical Hindi, and English. London: W. H. Allen & Co., 1884.
Mahendra Caturvedi. A practical Hindi-English dictionary. Delhi: National Publishing House, 1970.
Singh, Maya. The Panjabi dictionary. Lahore: Munshi Gulab Singh & Sons, 1895.
Turner, R. L. (Ralph Lilley), Sir. A comparative dictionary of Indo-Aryan languages. London: Oxford University Press, 1962-1966. Includes three supplements, published 1969-1
Parmanand Mewaram. A Sindhi-English dictionary. Hyderabad, Sind : The Sind Juvenile Co-operative Society, 1910.
University of Madras. Tamil lexicon. [Madras], University of Madras, 1924-1936.
Brown, Charles Philip. A Telugu-English dictionary. New ed., thoroughly rev. and brought up to date … 2nd ed. Madras: Promoting Christian Knowledge, 1903.
Burrow, T., and M. B. Emeneau. A Dravidian etymological dictionary. 2nd ed. Oxford [Oxfordshire]: Clarendon Press, 1984.
Wolf, Richard K. n.d. Kota Dictionary. Manuscript
Hayyim, Sulayman. New Persian-English dictionary, complete and modern, designed to give the English meanings of over 50,000 words, terms, idioms, and proverbs in the Persian language, as well as the transliteration of the words in English characters. Together with a sufficient treatment of all the grammatical features of the Persian Language. [Teheran, Librairie-imprimerie] 1934-1936.
Steingass, Francis Joseph. A Comprehensive Persian-English dictionary, including the Arabic words and phrases to be met with in Persian literature. London: Routledge & K. Paul, 1892.