Linux / Mac

Terminator

Originally created and developed for a long time by Chris Jones, the goal of this project is to produce a useful tool for arranging terminals. It is inspired by programs such as gnome-multi-term, quadkonsole, etc. in that the main focus is arranging terminals in grids (tabs is the most common default method, which Terminator also supports).

Oh My Zsh

A delightful community-driven (with 1,100+ contributors) framework for managing your zsh configuration. Includes 200+ optional plugins (rails, git, OSX, hub, capistrano, brew, ant, php, python, etc), over 140 themes to spice up your morning, and an auto-update tool so that makes it easy to keep up with the latest updates from the community.

Byobu

Formerly screen, this is a must-to-have if your development involves remote connections. It keeps terminal sessions (SSH) even if the client crashes, but also allows multiple tabs, split windows, shows information about the host, and some other bits and pieces.

Windows

MobaXTerm

Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more.

WinDirStat

Graphical overview of disk usage statistics

The Cloud

Trello / WeKan

Kanban style task managers with multiple users, very flexible, recommended for personal and professional use. WeKan is open source and can be installed in a server.