If you don't want to build a database from scratch, several "Extra Quality" mods are currently trending:
Modifying game databases can lead to account bans if used while connected to official EA servers (though FIFA 16 Mobile servers are largely sunset). Always play db editor fifa 16 mobile extra quality
refers to specialized tools used to modify the game's internal If you don't want to build a database
Advanced editors allow you to open the game tables directly to change league structures or add new leagues that weren't in the original game. Where to Find These Tools db editor fifa 16 mobile extra quality