The Witcher wiki now has a light themed alternative for the wiki skin. To check it out, go to Special:Preferences, then choose the "Appearance" tab and click on the radio button next to "Hydra".
Additional goods are items Geralt can obtain from the remains of beasts he has killed. They lack alchemical uses but some merchants will pay for them, and some quests require them. They do not usually require journal bestiary entries in order to be "available" to Geralt, unlike other skin-able items which do have alchemical uses. Below is a quick list of all the additional goods in the game and the best prices (remember, not every merchant gives the best price).