At the beginning of each draw step, Omen Machine prevents the active player from drawing a card, and causes them to exile the top card of their library, and cast that card if its a spell without paying its mana cost, or put it onto the battlefield if it's a land.
If an opponent casts a spell this way, Lavinia triggers, countering that spell.

All spells opponents cast using Omen Machine are countered

Players cannot draw cards

Lavinia, Azorius Renegade

Omen Machine

Omen Machine prevents players from putting more cards in their hand and Drannith Magistrate prevents players from casting the cards otherwise.

Opponents can only cast the remaining spells in their hand

Drannith Magistrate

Players cannot draw cards due to Omen Machine.
At the beginning of each player's draw step, Omen Machnie triggers, exiling the top card of that player's library and allowing them to cast it, if able.
Teferi only allows opponent to cast spells at sorcery speed, thus forbidding them from casting the cast exiled by Omen Machine, unless it is a land card.

Opponents can only play lands exiled by Omen Machine

Teferi, Time Raveler

At the beginning of each player's draw step, Omen Machine triggers, exiling the top card of their library, and putting the card onto the battlefield if it's a land, or causing its owner to cast it without paying its mana cost otherwise.
Because Soulless Jailer prevents noncreature spells from being cast from exile, no player may cast noncreature spells as permitted by Omen Machine.

Players cannot cast noncreature spells exiled by Omen Machine

Soulless Jailer

At the beginning of each draw step, Omen Machine prevents the active player from drawing a card, and causes them to exile the top card of their library, and cast that card if its a spell without paying its mana cost, or put it onto the battlefield if it's a land.
If a player casts a spell this way, Vexing Bauble triggers, countering that spell.

Vexing Bauble

Players cannot draw cards due to Omen Machine.
At the beginning of each player's draw step, Omen Machnie triggers, exiling the top card of that player's library and allowing them to cast it, if able.
Teferi only allows opponent to cast spells at sorcery speed, thus forbidding them from playing the card exiled by Omen Machine, unless it is a land card.

Combos with "Omen Machine"