I have used Toad for Oracle and Oracle SQL Developer. Those are both good for working with Oracle databases.

However, I generally prefer Open Source tools and ideally something that works with other databases as well.

So I looked around, tried TOra but found it buggy and too limited. Also, its development is quite slow, see commit history.

Then I came across DBeaver and liked it a lot. It is actively developed, the latest version 3.5.1 was actually released 3 days ago.

It is a cross-platform tool (Windows, Linux, MacOS, other Unixes) written in Java, uses the Eclipse framework for a lot of great out-of-the-box features and is overall quite polished.

It supports many databases via JDBC. More details and some comparison with similar tools are mentioned on its About page.