There is this python bot
https://github.com/ndri/python-bittrexI couldn´t get it to work, but thats because i must be doing something wrong with the code and i am not very literate in programming.
This is not a trading bot but some code to interact with bittrex. If you want to have a trading bot you need to code it on top of it.
If you are searching for trading bots, there are several here in the forum: Gunbot, CAS and there is one more where I forgot the name of it.