Adaptive Automaton

As Adaptive Automaton enters, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Secret Lair Drop

The Brothers' War Retro Artifacts

As Adaptive Automaton enters the battlefield, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Warhammer 40,000 Commander

Even though Adaptive Automaton is a Construct, other Construct creatures you control won't get +1/+1 unless you chose Construct as Adaptive Automaton entered the battlefield.

The choice of creature type is made as Adaptive Automaton enters the battlefield. Players can't take any actions between the time the choice is made and the time the appropriate creatures begin to get +1/+1.

You must choose an existing creature type, such as Human or Warrior. Card types such as artifact and supertypes such as legendary can't be chosen.