In my Street Urchin homebrew background, I gave them a Gaming Set for Tool Proficiency. I can see them doing some three-card monte to scam people out of their money so they can buy something to eat.Street Urchin
Ability Scores: Dexterity, Intelligence or Charisma
Feat: Alertness
Skills: Athletics, Stealth and Sleight of Hand
Tool Proficiency does not make sense for street urchin but if one had to be chosen instead of a third skill I would say Thieves Tools.
I was thinking something very similar for a Miner background.Laborer - Quarry
Ability Scores: Strength, Dexterity or Constitution
Feat: Toughness
Skills: Athletics and Intimidation
Tool Proficiency: Mason's Tools

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.