Turned out those scattered IPs were from a very small number of places, blocking these five killed 100% of my crawler spam: AS4229 Zenlayer (Singapore)

Turned out those scattered IPs were from a very small number of places, blocking these five killed 100% of my crawler spam: AS4229 Zenlayer (Singapore) PTE. LTD AS21859 ZEN-ECN, US AS45102 ALIBABA-CN-NET Alibaba US Technology Co., Ltd., CN AS132203 TENCENT-NET-AP-CN Tencent Building, Kejizhongyi Avenue, CN AS136907 HUAWEI INTERNATIONAL PTE. LTD. That's 4392 contiguous IP ranges.