The answer is the only 3 things that bring a witcher some joy on this cursed continent :
1. His Silver Sword
2. His steel sword
3. His "magic wand"
or maybe the magic wand is no 1? If the silver sword breaks there is a backup. If the appendage breaks theres only feeling sorry for yourself Theon Greyjoy style
Both monsters appeared in W1. Striga is woman transformed into monster by a curse while Zeugl is a slimy monster boss found in Vizima sewers in W1 if I'm not mistaken