It's specific per group. We usually talk about a certain thing a lot in a group. Sometimes it's pulling up an API document. Sometimes it's a huge group with a lot of parties and you just want a summary of a long conversation. Sometimes you want to highlight certain links or be up to date with certain items.
There's a lot of problems that slackbots can solve, but asking people what type of slackbot they would pay $10 a month for is not probably not going to generate a lot of viable business ideas.<p>Find out problems folks are having and from there narrow that list down to those that are easily solvable by slackbots.
Slackbots are way too specific to any particular group. You may have better luck with Discord bots since you can make more creative bots there (eg music and multimedia as opposed to "boring" office stuff).
A tomorrow's closing share price for aapl-bot. A latitude and longitude of my soul mate-bot. A formula for the cure for cancer-bot. A reason to give a damn-bot.