Milvus

Chroma is an open-source AI-native embedding database designed for building LLM applications. It provides simple APIs to store embeddings and perform similarity search, making it ideal for RAG applications.

Qdrant is a high-performance vector database widely used as the retrieval layer for RAG and agent memory search scenarios.

Weaviate is an open-source vector database that stores objects and vectors, allowing for combining vector search with structured filtering. It has built-in vectorization modules and supports multimodal data search.

Haystack is an enterprise-grade framework for RAG and search applications, covering document processing, retrieval, generation, and evaluation end to end.