The Serializable API remains one of the most significant liabilities to Java application security. In particular, it brings a substantial share of vulnerabilities related to insecure deserialization entry points and gadget chains to exploit them. The latter can be attributed in large part to the gadget chain payload generator Ysoserial. With its undeniable value for penetration testing and research, it is regrettable that this tool received its last update in 2021. Not only does Ysoserial lack recent gadget chains, but its rigid architecture makes it hard to reuse or adapt gadgets. Such modifications are, however, crucial to bypass security measures in current Java versions. In this work, we overcome these deficiencies by designing the new payload generator GadgetBuilder. Our tool combines 31 main gadget chains in Ysoserial with 29 chains from other sources. It splits up the gadget chain construction into three gadget chain fragments. This abstraction increases the effective number of gadget chains to 303. Further, by using recent gadgets, 17 of the Ysoserial gadget chains become viable again for recent Java versions (16 and above). It also increases the attack surface against Java deserialization filters. Thereby, our work facilitates a much-needed update to Ysoserial that provides security researchers with a comprehensive overview of deserialization gadget chains.