ZettelTalk

website: https://international.bittrex.com/

looks like listing is free if you have "legal opinion letter from a Maltese law firm confirming that the token is a Virtual Financial Asset (VFA) and not a financial instrument" :
https://bittrex.zendesk.com/hc/en-us/ar ... Compliance

listing form: https://bittrex.zendesk.com/hc/en-us/re ... 4093958872

support: https://twitter.com/BittrexExchange

As part of its review, Bittrex takes into consideration a number of factors including but not limited to:

New blockchain features
Significant improvement over existing blockchain
Interesting, innovative, or unique application
Usefulness of use cases
Technological experience and reputation of token applicant and team
Market interest