ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
UnderPinned - One app to manage your projects from start to finish.
fusebill - Fusebill is the leading recurring billing and subscription management software for businesses. Try Fusebill for subscription billing made easy!
Tapwater - All project details. One place.
Elorus - A super-easy online invoicing & time tracking software
Planning Poker - Open source implementation of planning poker game (collaborative online estimation/voting tool).