LlamaIndex

From LlamaIndex docs

Chat Engine - Best Mode - LlamaIndex

Langchain

[Beta] Memory | 🦜️🔗 LangChain

LLM RAG Chatbot using Langchain

Build an LLM RAG Chatbot With LangChain – Real Python

Different ways to implement conversational memory with Langchain

Conversational Memory for LLMs with Langchain