Qinco is an open-source implementation from Facebook Research for Residual Quantization with Implicit Neural Codebooks. It provides quantization and indexing methods for compact vector representations to accelerate similarity and nearest neighbor search, making it relevant as a low-level vector indexing and compression component for vector databases and large-scale AI retrieval systems.

Arroy is an open-source library for efficient similarity search and management of vector embeddings, useful in vector database systems.

Epsilla is an open-source vector database optimized for high-performance similarity search and scalable storage of vector embeddings.

HVS is a graph-based index structure leveraging Voronoi diagrams for approximate nearest neighbor search in high-dimensional vector spaces. It is directly relevant to vector databases as it provides efficient similarity search capabilities for large-scale vector data.

KGraph is an open-source library for fast approximate nearest neighbor search in high-dimensional vector spaces, applicable to vector database solutions.

MuopDB is an open-source vector database designed for fast and scalable similarity search in AI applications.