I found out that on Android contacts, at least HTC Sense stores Facebook ID with the following mimetype: vnd.android.cursor.item/vnd.facebook.profile this differs from their mimetype format such as com.htc.socialnetwork.facebook/smallavatar
I am wondering where do I find a list of officially supported mimetypes for Android?
There are no "officially supported mimetypes for Android" except to the extent they are documented in random spots in the Android SDK, usually as CONTENT_TYPE public static data members (e.g., android.provider.ContactsContract.Contacts.CONTENT_TYPE).
To the best of my knowledge, there is no HTC Sense SDK, and therefore there are no "officially supported mimetypes for Android" related to anything in any version of Sense.