Many "keygens" or "cracks" downloaded from unverified sources contain hidden Trojans that can steal banking information or install ransomware.
Serialwz (often a variation or typo of "Serials WZ" or similar serial number repositories) generally refers to a category of websites dedicated to the aggregation of serial numbers, product keys, and cracks for software applications. Historically, these sites functioned as massive, searchable databases. If a user installed a copy of Adobe Photoshop or a PC game but lacked the mandatory license key to activate it, they would turn to sites like Serialwz.