Kishimoto was such a fucking bum for making Tobirama the inventor of every fucking jutsu.
FTG should've been unique to Minato.
Tobirama should've had his own techniques.
Shadow Clones should've been invented by the Uzumaki's or Senju, since they're so blessed with vitality, or maybe some other mentioned clan like the Sarutobi, or Hagoromo (mentioned in passing and possible distant relatives to Senju/etc).