Raclette is a cheese that comes originally from Central Switzerland. In the Middle Ages they made a cheese known as Brätchäs, or roasting cheese. A form of this is still made there today, another form made its way west where it got renamed 'Raclette'. Somehow, it got a French name (from the word Raclerre, which means 'to scrape') even thugh it is most popular and mostly made in German speaking regions.
Originally, raclette was either eaten as is, or else held next to a fire or hot oven so that the surface would melt, this then being scraped off onto bread, potatoes, or sausage.
This became a whole meal, named after the cheese.
In recent times, a special grill device was invented to make the melting easier. This was then also called a raclette. So the name gets used a lot these days.
The traditional cheese for this is the original Raclette. It is ideally suited, since the cheese is made just for this purpose.
Any melting cheese works for this to some degree. Think of what cheese you like on a hot sandwich or in Fondue, those are what you like for melting cheeses.
In general, any washed curd cheese is suitable