Whenever you scry or surveil, draw a card. (Draw after you scry or surveil.)
Matoya turns every scry and surveil into a free card, so you flood the board with cheap scry/surveil engines and convert them into a relentless card-advantage stream. Spend the early turns deploying repeatable scry sources and defensive pieces, then leverage the resulting card flow to land a control suite or an overwhelming combo/finisher in mono-blue.
Massive, repeatable card advantage that snowballs from cheap permanents
Mono-blue consistency makes mana and color screw rare
Scry/surveil sources are abundant and often dirt cheap, so the engine is easy to assemble
Card-selection plus card-draw lets you dig to answers and win conditions reliably
Matoya itself does nothing without scry/surveil enablers in hand or play
Mono-blue lacks efficient removal and especially struggles versus resilient enchantments and artifacts
Heavy reliance on the commander invites removal; recasts get expensive fast
Can draw cards without a fast clock, leaving you behind aggressive boards
Some scry effects are one-shot, so consistency depends on permanent-based engines
With Matoya churning your library, decking yourself becomes a real plan, so a self-mill payoff closes games.
Prioritize permanent-based scry/surveil engines (Crystal Ball, Scrying Sheets, Thassa) over one-shot effects so triggers fire every turn without spending cards. Add upkeep/trigger doublers like Sphinx of the Second Sun and protection for Matoya (Lightning Greaves, counterspells) since the commander is your engine's heart. To raise the ceiling, lean into a tight mono-blue combo finish such as Thassa's Oracle plus self-mill or an infinite-draw loop the card flow naturally supports.