SurrealDB

vs

IBM DB2

Supabase is a free and open-source self-hosted and SaaS provided alternative to Firebase. With Supabase you can add a realtime REST API to a PostgreSQL without writing a single line of code.

Fauna is the data API for client-serverless applications. It provides web-native GraphQL interface, with support for custom business logic and integration with the serverless ecosystem. Fauna transforms the traditional DBMS into a Data API that gives you all of the capabilities of traditional database, without sacrificing flexibility, scale, and performance. By utilizing a globally-distributed storage and compute fabric, Fauna-powered applications are delivered to end-users fast and reliably on modern security infrastructure.

EdgeDB is a database designed on top of Postgres with the goal of eliminating some of the shortcommings of relation and NoSQL databases.  At first glance, EdgeDB looks like a regular object relational mapper (ORM), however it's far more than that, It's a full-fledged database with a formally-defined query language, a migrations system, a suite of client libraries in different languages, a command line tool, and a soon comming cloud hosting platform. The goal of EdgeDB has been to rethink every aspect of how developers model, migrate, manage, and query their database.

RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.

BigchainDB allows developers and enterprise to deploy blockchain proof-of-concepts, platforms and applications with a blockchain database, supporting a wide range of industries and use cases. BigchainDB provides high throughput, low latency, powerful query functionality, decentralized control, immutable data storage and built-in asset support, BigchainDB is like a database with blockchain characteristics.

NuoDB is a distributed relational database management system utilizing SQL. The database is architected to meet the rapidly evolving demands of today's enterprises, NuoDB can be used to deploy on-premise, extend to the cloud, scale on demand, eliminate downtime and reduce total cost of ownership. All while maintaining SQL compatibility and a workflow that most developers are familiar with.