I downloaded Oracle's ADO.net connector and added support for it in my database classes. That meant that I could access Oracle databases from my console and WinForms apps, including one that allows the user to enter ad hoc queries and view the schema.
SQLTools[^] if you want it lightweight. TOra[^] is at the other end of the spectrum.
Both are opensource.
SQL Developer and Oracle Developer Tools for Visual Studio has already been mentioned. They are from Oracle and are supported, ... sort of.
You will also need to install some version of the Oracle Client which is available in several versions such as the normal Client, Instant Client or Oracle Data Provider for Dotnet.
Oracle Developer Tools for Visual Studio has the Client built in.
I had a programmer in a foreign country develop an application for me, I had to dismiss him because he would not finish the program on time. I asked him for the source code to MySQL db and he would not provide it. I paid him so that wasn't the issue. I need to move my application from one cloud server to another company and I need help in figuring out how to break the db code to move the application. There are a lot of connection points in and out of the db so I can't just copy the db and move it over.