frugal is an open-source, self-hosted platform for AI/ML operations with vector database support, focusing on cost optimization and transparency. Key features include model-agnostic tracking, alerting, caching, and free use. Useful for RAG prototypes monitoring costs, self-hosted alternative to managed services like Pinecone for reduced expenses.

NGT (Neighborhood Graph and Tree) is an open-source vector search engine designed for fast and scalable approximate nearest neighbor search.

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

Valkey is an open-source in-memory key-value data store that supports vector search operations, making it useful for AI and machine learning vector database workloads. It is also a specialized open-source vector database designed for efficient management and retrieval of high-dimensional vector data, offering advanced APIs and optimized storage for AI workloads.

ClickHouse is a columnar OLAP database with vector indexes (ANN via AMM, brute-force), supporting SQL queries over vectors + structured data at petabyte scale. Excels in aggregations with vectors. For analytics workloads with embeddings; faster ingestion than Postgres pgvector for big data.

A curated collection of open-source vector database projects, providing a centralized list for exploring and comparing solutions designed for vector search and AI applications.