What are currants? Can something else be used as a substitute when making rugelach?

Truth is, Rugulach can be filled with any preserves you like. Apricot is a big favorite, also raspberry. Boysenberry is my favorite! Chopped chocolate is also very popular. The traditional rugulach has cinnamon, walnuts and currants. If you use raisins in this combo, chop them teeny (like currants). But you don't need nuts, or cinnamon or raisins to make delicious rugulach. Imho their true deliciousness lies in the dough you use for the cookie. I make Maida Heatter's recipe of a cream cheese cooky dough. I don't like the ones with yeast.

As explained above, currants are smaller than raisins. I don't think raisins are "too big" for rugelach but if you wanted to be picky, you could snip raisins or other dried fruits with a scissors into smaller pieces. Spray the scissors blades with some vegetable cooking spray to keep the dried fruit from sticking.

To answer your first question, currants are a grape cultivar--and one of the oldest grapes to be used as raisins.

Figs sounds like a great idea! Golden raisins and dried cranberries would also be an option.

Monita has it right. Purple raisins are the closest substitute, but diced, dried figs could also be a tasty substitute with a slightly different flavor.

Currents look like raisins; just smaller. You can absolutely substitute with any dried fruit, especially raisins