[richardknop]

Terminal (this is a requirement if you want to do any software related job other than .NET I guess), some sort of a text editor with code code highlighting (Sublime), internet browser (reading documentation is a big part of my job), email client (reading & replying to work emails), version control (git).

Those are basics but there are additional tools which you'll probably need to use daily as well (JIRA, Slack or their equivalents, for example).