Hi I am Pakistani national and working in Romania. I have residence permit long term. please advise which countries I can travel visa free with Romanian residence permit. thanks
Wikipedia has an article in Visa requirements for Pakistani citizens which at the time of writing lists 31 countries that are visa-free or visa-on-arrival for Pakistanis.
As Romania is not yet part of the Schengen area your Romanian residence permit doesn't allow you access to Schengen countries, but according to the Wikipedia article on the Schengen Visa Policy you can enter Bulgaria, Croatia and Cyprus.
Your question is, however, rather broad and I don't claim that this answer is exhaustive. If there is some country you'd like to visit you would do better asking about the specific visa requirements for that country.