Mastodon apps for Android: Tusky, Fedilab
Mastodon apps for iOS: Toot!, Mast, Amaroq
There is no app called “Mastodon” because anyone can develop an app (and the aforementioned ones are made by independent developers). You can also use the website on your phone, it works quite well and has 100% of the features.
For a more complete list of apps see https://joinmastodon.org/apps
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!