Depending on the lender, the types of mortgages available to the BTL borrower are usually the same as those available to the standard residential mortgage borrower — i.e., tracker, discount, fixed rate, capped rate and variable rate.
Given that most BTL borrowers buy for reasons of investment, some mortgage options may be more appropriate than others. With a fixed-rate mortgage for example, the borrower knows exactly what their monthly repayments are going to be; other borrowers prefer tracker or variable rate loans where the monthly repayment can sometimes be lower, but the cost can vary from one month to the next.
(Many BTL buyers have a preference for interest only mortgages, as distinct to a capital and interest repayment mortgage. An interest only mortgage, is a mortgage where the monthly repayment is used solely to pay off the interest on the loan but none of the capital, which is repaid only when the property is sold.)