Each creditor determines which CRA or CRA's they use. It's unreasonable to expect us to list every creditor that uses one of the CRA's. You can browse the Credit Pulls Database (Google to find) and existing threads.
While you find that TU is most commonly pulled for you, others can find that another CRA is used more often. EQ is pulled more often for me.
Hard pulls are generally a small factor. If you're seeing major impact due to pulls then you have bigger issues with your credit profile that you need to address.
