As the block slides down the ramp, what type of energy conversion is occurring?

As a block slides down a ramp the potential energy is transformed into kinetic energy.

If there is not friction between the ramp and the block that is the only conversion occurring.

If there is friction some potential energy will be converted into thermal energy (heat) and sound.

Also, if there is any kind of interaction between the block and other object some other kind of energies can be otained.

That is all what can be said without a figure that shows other specific condition that implies another conversion of energy.