Frozen Goodies - An advent calendar to get the chance to win daily prizes
Votum for Slack - Crowdsourced lists with upvotes, inside Slack
Mimry - Your own personal stylist for $5 a month
Must-Read for Slack - Build controllable must-read lists for your team in Slack.
UXmas - An advent calendar for UX folk
Corpus - Curate, take notes and share your reading list