Best Form Builder for Slack
The reference presents itself as the best form builder for Slack; that integration is not built here, so there is no counterpart.
In the reference help centre this page argues for the reference product as a form builder for Slack: why requests posted as messages get lost, how each submission is posted to a channel through the reference's native integration, a list of free features, and use cases such as internal requests, bug reports and feedback.
Tinyform has no counterpart to this page because the Slack integration it rests on is not yet available here. A form can still hand its answers on: email notifications reach an inbox the moment a submission lands, webhooks post each submission to an address you choose, and the REST API reads them back. Any of those can be wired into a chat tool by an automation of your own, but that is not something this product does natively and this help centre does not claim otherwise.