HeidiSQL not supported for 4 years ? This is a joke i hope
You have nightly every week... Only pb with Heidi is the source is in pascal like
Database tool:
HeidiSQL is a must have, for me far over Navicat / MySQL Workbench who are fastidious and heavy machines. Navicat is better in database types supported, while MySQL workbench integrates correctly with mysql tool suite (database schema design etc...). But heidisql got a clear interface, quick navigation and is opensource. HeidiSQL supports MySQL/MariaDB, PostgreSQL and SQL server. I don't have any crash with Heidi, and it performs better when importing large mysql dumps than a lot of tools i have tested altough like Hunabku suggests, command line is better for this task.
Database engine:
MariaDB is the natural evolution since Oracle bought Mysql. I personnaly stick to 3 DB engines: MariaDB, PostgreSQL and SQLite. I have not really worked with MongoDB or any no-SQL database.
IDE:
SharpDevelop is doing the job. Similar to HeidiSQL, it hides the (sometimes very big) complexity of Visual Studio and is finally a perfect tool between VS express edition. Sadly SD is no longer maintained. Visual Studio Community is a nearly complete Visual Studio, but is more complex and not lightweigth at all. For business use, i'm using Visual Studio, but i suggest to stick to SD as long as you can. I have few experience with MonoDevelop, but this one is at least working on macOS.