Unapp - A directory of minimal and useful single-purpose apps.
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
BotList - An app store for bots
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Slack App Directory - Your go-to for finding apps that work with Slack
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community