+1/+1 counter shenanigans. Hand `em out like candy, and make Kraj into a crazy multitool.
Do the simic ramp thing and get Kraj up and running. Spread around +1/+1 counters to make your board big and scary, and make Kraj into a weird multitool that can get pretty out of control. Mostly just fair battle-cruisery magic backed up by a tutor suite and some strong synergy between your creatures
Getting a +1/+1 counter onto something that can untap Kraj is a good way to supercharge your gameplan. Good targets are Horseshoe Crab, Pili-Pala, and Gilder Bairn.
Graft triggers whenever any creature enters, so you can graft on to your opponents' creatures if they have sweet activated abilities for kraj to use (or to steal with Cytoplast Manipulator!).
A good way to end the game is to get Herald of Secret Streams on board so your attacks go unblocked. Nice with a giant ooze.
Apparently, Incubation Sage goes infinite with a lot of parts of this deck.
You can remove some of the tutors and Incubation Sage, and you'll probably be safe to play this at most Bracket 3 tables.