(Check back in as I add details on how I use each, the features I like, and how I integrate everything together into dashboards for myself and clients)
Project Management (planning & estimation)
Arbor makes creating backlog, organizing projects and themes, and estimating really easy. Arbor allows for simple integration between slack and trello (see below for more info on them) which makes it easy to collaborate.
Task Tracking
Trello is quick and simple kanban task management. With the ability to create custom states it makes it easy to provide detailed status reports.
Communication
Slack
tinyletter
Dashboards
DashZen
Cyfe
TheDash
Integration
Zapier
Testing
GhostInspector
Runscope
Invoicing
Ronin
Presentations
reveal.js
Version Control
GitHub
BitBucket
GitLab.io
Prototyping
Marvel