Cottontail DB is an open-source vector database for storing and searching high-dimensional data, with features geared towards research and production environments.

OasysDB is an open-source vector database focused on efficient similarity search and management of high-dimensional data.

NMSLIB is an efficient similarity search library and toolkit for high-dimensional vector spaces, supporting a variety of indexing algorithms for vector database use cases.

Qdrant is a dedicated vector database and similarity search engine supporting advanced filtering and efficient retrieval, suitable for faceted search and retrieval-augmented generation. It offers self-hosted and cloud deployment options, making it highly relevant for vector search applications.

IDEA is an inverted, deduplication-aware index structure designed to improve storage efficiency and query performance for similarity search workloads. It is implemented as research code and targets high-dimensional vector and content-addressable data, making it relevant to large-scale vector database and ANN indexing systems.

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.