Well if there are any official website for the wallet please provide one. Even if I found one in play store I wouldn't be sure if its real or fake. I should stick to the Bitcoin experts.
Electrum wallet -->>
https://electrum.org (Do not just trust, verify. Please make sure you first Verify GPG signatures before you install the wallet)
Unstoppable wallet -->>
https://horizontalsystems.io (you will get links to their github from the site) This one supports Bitcoin and some altcoins