The 24-year-old has been a free-scoring presence for Gainsborough Trinity and Alfreton Town since leaving boyhood club Sheffield Wednesday.
He arrives at the Jakemans Community Stadium, on a free transfer, on a two-year deal.
Waldock was an opponent of the Pilgrims during their 2023-2024 promotion-winning campaign.
He will link up with the Pilgrims at the start of July, as the club transition to their full-time model.