Interestly, I tried to google for periapt of wisdom. I figured it would set the ability score to 16 or something. Oddly enough, 5e does NOT have an official necklace like it directly. Third party has them increase Wisdom by +2 (able to go beyond 20). So could you get your DM to 'allow' you to find such a necklace. Wisdom of 16 while attuned shouldn't be too OP, right?