Riftbound Mill Deck Guide: Control Shell, Win Plan, and Testing Checklist
Plan a Riftbound mill deck shell with control tools, recursion pressure, defensive sequencing, and matchup tests before publishing a list.

A Riftbound mill deck is a control idea first and a deck-out plan second. If the list cannot survive battlefields, it will lose before the opponent's deck size matters.
Quick answer
build Riftbound mill as a defensive control shell with resource pressure, repeated interaction, card flow, and a real scoring plan. Do not rely on mill as the only way to win unless testing proves the format gives you enough time.
Use the card database to search for discard, banish, draw, recycle, hidden, and recursion effects, then test the list in the deck builder.
The Mill Deck Problem

Mind/Chaos Legend
Teemo - Swift Scout
Teemo-style control and hidden-card pressure are useful search points for Riftbound mill and fatigue shells.
Mill decks are tempting because they give you a different angle of attack. The risk is that Riftbound still asks players to fight over battlefields and points. If you spend the whole game interacting with the opponent's deck but never contest the map, you are not controlling the game.
The best version of this shell should make the opponent's hand and deck awkward while still scoring enough to force action.
Core Shell
Start with jobs instead of exact cards.
A mill deck that has no finishers can lose after doing the hard work. A mill deck that has no early defense never reaches its engine turn.
Mulligan Plan
Against aggressive decks, mulligan for early bodies and cheap interaction. Against slower decks, keep card flow plus an engine piece. Against tempo decks, keep hands that can answer the first battlefield pivot.
Do not keep a hand just because it has the coolest mill card. If the hand does not play before the opponent scores, it is probably too slow.
Matchups To Test
Test the shell against pressure first.
If you only test into slow decks, the list will look better than it is.
Common Mistakes
The biggest mistake is treating mill as a substitute for winning battlefields. It is not. Resource pressure is how you make the opponent's future turns worse; it does not automatically win this turn's score.
The second mistake is playing too many narrow cards. If a card only matters when the opponent is already low on deck or hand resources, it may be dead in the games where you most need help.
Bottom Line
A Riftbound mill deck should be built like a control deck with a resource-pressure finish. Survive the first battlefields, trade efficiently, pressure the opponent's future turns, and keep a real scoring route in the list.