Database NoSQL
BaseX is a native XML database. It features compact storage structures, a very efficient XPath and XQuery implementation and a visual frontend, facilitating visual access to the stored data. BaseX is written in Java and freely available for download. It is developed by the Database and Information Systems Group at the University of Konstanz.
Corpus-DB is a textual corpus database for the digital humanities. This project adds public domain texts, enhances their metadata from sources such as Wikipedia, and makes those texts available according to that metadata.
eXist-db is an open source software project for NoSQL databases built on XML technology. It is classified as both a NoSQL document-oriented database system and a native XML database. Unlike most relational database management systems (RDBMS) and NoSQL databases, eXist-db provides XQuery and XSLT as its query and application programming languages.
MongoDB is a distributed database, the horizontal scaling, and geographic distribution are built in and easy to use. MongoDB uses JSON-type documents and is easy to integrate.
Redis is based on key-value storage, it stores all kinds of data, from strings, hashes, lists, etc.
Cassandra uses key-value storage, is a distributed and massively scalable NoSQL DBMS.
Database SQL
MySQL is a relational database management system widely used on today's websites.
MariaDB the main characteristics are: increased storage engines, great scalability, security and speed in transactions, extensions and new features related to its application for NoSQL databases.
SQLite the main characteristics are: the size, much smaller than any DBMS, great stability, high portability and performance.
PostgreSQL the main characteristics are: multi-version control of concurrences, flexibility in terms of programming languages, multiplatform, it has the pgAdmin tool, https://www.pgadmin.org/, for the administration of the databases, robust, efficient and stable.
Oracle the main characteristics are: transaction support, stability, scalability and multi-platform (there is a free version).