Your room is magenta what other colors would go with it well?

If you have painted your wall(s) magenta then I recommend you go to neutral colours for the rest of the room. White or pearl grey light fabric for your window coverings. A similar grey for the carpeting or other flooring (white is just not practical for a floor). If this is a bedroom, white linens (sheets, pillow cases etc) and a paterned bedspread (duvet cover or quilt) with as close a match to the magenta as possible in the patern. Furniture (desks, dressers, etc) can be either a light wood or if you are ready to paint it, a grey to match (or slightly lighter than your carpet/flooring. The trim work (baseboards, window and door casings and other mouldings) will look great in white.

If you haven't committed to painting the walls magenta yet, you may want to try a "focal wall" Pick one wall, in a bedroom it is usually the wall directly opposite the entry door and/or the wall you have the head of a standard bed (or the long side of a daybed or mates bed) on. Paint this wall magenta and then paint the other three walls something else. If you are not adverse to pink, you can take the colour chip for the magenta and more up the scale for a lighter but related pastel pink. If pink is not an option, try a pastel of one of your other favourite colours. For inspiration, you may want to purchase a duvet cover that has the magenta in the pattern (as suggested above) and pick one of the other colour from it. Neutrals also work well, a pale pearl (cool) grey for the walls, and a medium (cool) grey for the flooring and furniture, white trim and ceiling and if you can find it either a fabric to match your duvet cover or sheer magenta window treatments.

In both cases, touches of black, please note I said touches, will give the room grounding