Costumes, hairstyles and other smaller DLCs The Witcher 3 Guide
Beard and Hairstyle Set

This expansion allows you to change the looks of Geralt. Thanks to it, you can go to barber and change the hair and beard style. The expansion adds 4 new hairstyles and 4 beard types, while in the basic version you could only cut the latter. To use the DLC, all you need to do is visit any barber after installing the expansion.
Alternative look for Yennefer

This DLC allows you to change Yennefer's look. The look will change permanently, also for the older game saves. This modification will change the dress to perfectly black, with no white parts, and with slightly different fashion.
Alternative look for Triss

By installing this expansion you will change Triss' look. Instead of her regular outfit, she will now wear a dress in dark green color with white parts. A small chain will appear on her forehead as well.
Alternative look for Ciri

This expansion will change Ciri's look for the entire game. Instead of a simple, peasant outfit, she will receive a witcher outfit as her new default one.
New Finisher Animations
It's a small set of finishers, the attacks that end the battle. In addition to the previously available head cuts or pushing the sword into the stomach, new animations are added, such as cutting the legs near the ankles. You should definitely install this set, as, in difference to many other DLCs, it doesn't replace the previous animations, but only adds new ones. The finishers are activated after killing the enemy, in random way. Despite that, you should quickly notice the new ones.
Ballad Heroes - Neutral Gwent Card Set

The name can be deceiving. It's not a completely new, independent card set, which you could use during the Gwent games. It's only a set of new skins for the cards. They look more interesting than the previous version of the images, but this expansion doesn't add anything else.