2 cards where the text includes “+1/+1” and the text includes “counter” and the colors is GU and it’s legal in Standard

Slogurk, the Overslime {1}{G}{U}

Legendary Creature — Ooze

Trample

Whenever a land card is put into your graveyard from anywhere, put a +1/+1 counter on Slogurk, the Overslime.

Remove three +1/+1 counters from Slogurk: Return it to its owner’s hand.

When Slogurk leaves the battlefield, return up to three target land cards from your graveyard to your hand.

3/3

Illustrated by Nicholas Gregory

Standard
Alchemy
Pioneer
Explorer
Modern
Brawl
Legacy
Historic
Vintage
Pauper
Commander
Penny

Winterthorn Blessing {G}{U}

Sorcery

Put a +1/+1 counter on up to one target creature you control. Tap up to one target creature you don’t control, and that creature doesn’t untap during its controller’s next untap step.

Flashback {1}{G}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Illustrated by Yeong-Hao Han

Standard
Alchemy
Pioneer
Explorer
Modern
Brawl
Legacy
Historic
Vintage
Pauper
Commander
Penny

The message was clear to Sorin—time to search for something else.