Yes, agree with FHM, although in smaller filters, sponge is often used to play the biomedia role, rather than the dedicated biomedia types mentioned.
For beginners its always good to take a moment when you have the chance and learn the basics: Filters have 3 functions, mechanical, chemical and biological filtration. Nearly every media type will overlap functionalities. Mechanical is the trapping of debris and particals, chemical is custom alteration of the water usually via the use of charge attractions on the chemical level and biological is the "cycling" function you're already familiar with no doubt.
Chemical filtration is only needed when its needed, in special cases. Carbon (aka activated charcoal) falls into this category. Its good to have on the shelf but not needed on a regular basis. Its good for removing medications, removing yellow tannins from bogwood and removing unusual organic odors on occasion, but it accomplishes its work in about 3 days and then is ready to be removed and discarded. Zeolite and a few other things fall into the "chemical media" category.
Just about anything you put in a filter box will overlap on accomplishing a certain amount of both mechanical and biological filtration. Sponges are especially good at both. They perform excellent mechanical filtration and are competitive with the best ceramics at being among the top biological performers. The ceramics only outperform sponges in that they last forever, whereas a sponge will eventually break down and need replacement. Polyfloss, whether loose or in shaped pads, is a fine particle mechanical filter, for water polishing, as FHM says. It also collects bacteria but is not a good biological media in that it needs frequent replacement, when it breaks down.
Hope that helps. There have been other discussions of this sort probably findable by search.
~~waterdrop~~
