Molly is a hardened version of the official Signal for Android app. It claims the following features,

• Protects database with passphrase encryption
• Locks down the app automatically after you go a certain time without unlocking your device
• Securely shreds sensitive data from RAM
• Allows you to delete contacts and stop sharing your profile
• Clears call notifications together with expiring messages
• Disables debug logs
• No SMS integration

There are two flavors of it,

• Molly - Similar to the official Signal app, plus the additional features
• Molly-FOSS - Doesn’t rely on any Google components for location, push notifications