I downloaded the icons I needed from here. They are from no particular icon pack. I just selected the icons which I felt would fit in well with the theme I was going for and then edited them onto the wallpaper background images on my computer. It’s a tedious process but it becomes easy once you get used to it and the result is worth it ;). Source: about 2 years ago

Icons 8 (Free but sometimes they charge for full Res). Source: almost 3 years ago

Https://icons8.com/icons/ios You can use them by putting this link "https://img.icons8.com/ios/250/000000/icon.png" and just replace the word icon with the name of the icon (with spaces with replaced by a dash). Source: about 3 years ago

Hey HN! I am asking out of genuine curiosity, and perhaps doing a little market research. My team uses https://www.donut.com/ and https://officevibe.com/ but I'm pretty sure we're on the free tier for both. Do you work in a team that pays monthly for any cool Slack apps or integrations? Which ones? If you're not the one paying, do you find it useful - or annoying? Cheers! - Source: Hacker News / over 1 year ago

Officevibe, which is an employee experience platform, regularly sends out Slack notifications on behalf of their customers asking employees to complete a brief survey. Their engineering team utilizes the Automations API to create lists of users for whom the Slack survey could not be delivered and send them an email survey instead. - Source: dev.to / almost 2 years ago