Free speech supporters are going to love using Gab.ai, a social network that has had their mobile app banned from both Google Play and the App Store, for failing to comply with their policies on adult content. Be it as it may, Gab.ai still offers shelter to people who think that hate speech or non-art related public nudity is somehow okay in the public domain. However, you really have to look for unsavory content, and most of the posts on the platform are dedicated to memes, pop culture or art.
We Heart It is another popular image sharing platform similar to Imgur, but its content is very feminine, primarily made of inspirational photos and quotes that appeal to young women. Instagrammers who love inspirational content might really love this app not just for the content but for connecting to very positive and inspirational users in the community too.
A simple chat (slack style) it's enough. Just having the possibility to send messages either single user or team (#channel). But please don't forgive to give an useful appeal to mobile app (worst error of competitors is, have a good app but totally no mobile friendly!) i would expect to have a similar whatsapp or slack app for messaging within the slack mobile app!