Rowdy Crew

Trample
When Rowdy Crew enters, draw three cards, then discard two cards at random. If two cards that share a card type are discarded this way, put two +1/+1 counters on Rowdy Crew.

Ixalan

Trample
When Rowdy Crew enters the battlefield, draw three cards, then discard two cards at random. If two cards that share a card type are discarded this way, put two +1/+1 counters on Rowdy Crew.

Ixalan Promos

Once Rowdy Crew's triggered ability begins to resolve, no player may take other actions until it's done. Notably, you can't discard or cast any of the cards you draw to try to rig the results of the random discard.

Rowdy Crew doesn't get more than two +1/+1 counters if the discarded cards happen to share more than one card type.

The card types that can appear on the discarded cards are artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery. Legendary is a supertype, not a card type.

The discarded cards just need to share one card type. For example, Rowdy Crew will get two +1/+1 counters if you discard an artifact creature and an enchantment creature.