The best build for a rogue mastermind, in D&D 5e, is Halfling Rogue (Thief).
The Halfling’s small size allows it to sneak up on larger foes and steal their loot.
Their natural stealth coupled with the Thieves’ Cant come in handy for any curious character looking for a challenge! Their innately higher dexterity and speed provide additional benefits. Whichever you choose, the smallest race always has its advantages.
In addition to your skill sets that first-timers will find useful like Acrobatics or Athlete, an elusive Stealth or even Inquisitive type of background can help shape your uncanny ability to stay up only three feet from the enemies while they remain unaware of your escape paths.
Other sources for rogue builds include:
* Dungeon Master’s Guide
* Player’s Handbook
* Xanathar’s Guide to Everything