Unless you are a spellcaster Intelligence is underrated in 5e. Make Intelligence (at least) meaningful.
If you are a melee class (i.e. D&D Fighter) there is no reason whatsoever to have Intelligence at lower level.
Intelligence doesn't give you anything except excellence in checks involving Intelligence.
The same happens with Charisma, and Wisdom at some level, but Wisdom saves will resist mental effects so is even more useful.
Maybe give you an extra 1d4 bonus on checks with one skill specialty (i.e. Climb, Jump, or Swim for Athletics) per Intelligence modifier.