If you're using a free Slack account for your public community, we offer free Tettra accounts for storing knowledge. Community accounts must be public.
Here's and example of a public community: https://app.tettra.co/teams/growthdrivendesign
If you want to convert your existing Tettra account to a community account, get in touch and we can convert the account for you.
To create a new community account, sign up here: https://tettra.co/slack-community-wiki/