the amount of furniture you can fit on a general purpose rifle is very varied. It just comes down to what you like. As Samurai said, look on the internet. its a chance to express yourself and make your G26 different to everybody elses.
It amazes me when people say what gun shall I buy, what shall I fit on it. Its one of the few freedoms we have and to me, its one of the most enjoyable parts of guns.
Bear in mind, the more you add, the heavier it will be to lug round all game.
Personally, I love suppressors - have them on nearly every SMG and rifle. I especially like those that look like suppressors but make the noise louder.
Just check what thread you have i.e. CW or CCW and make sure you order the right one.