Offset-Vector Compaction (OVC) algorithms, such as the Compressor, are among the most widely deployed garbage collectors today, yet they have remained largely unexplored by the literature since the earliest algorithms were published two decades ago. Although an implementation in the Android Runtime is publicly available and a number of other variations on the algorithm have been developed or proposed, these have not been analyzed or evaluated with recent benchmarks or compared with modern server collectors. This gap in the literature may curtail innovation and exploration of new ideas while reinforcing unchallenged conventional wisdom. This paper makes six major contributions. We: i) introduce a taxonomy of offset-vector compaction (OVC) algorithms; ii) review the history of OVC algorithms, including the Compressor, discovering designs that were previously unreported; iii) implement a family of offset-vector compactors in OpenJDK; iv) implement and evaluate for the first time the One Pass (OP) Compactor; v) introduce a branch-free algorithm for computing forwarding information; and vi) conduct the first evaluation of offset-vector compactors on OpenJDK with modern workloads. We find that some of the variations we explore offer improvements over the original Compressor algorithm. We also find that, interestingly, the optimization proposed by the one pass (OP) Compactor does not improve over the Compressor. Our implementations are open source, allowing others to build on them. We hope that our analysis and evaluation of this important family of garbage collectors will enable future innovation and improved designs.