Here is a list of games currently integrated with Google Play Games Services. Most are free and are actually quite good (if developers take the time to add support for Google play game services, then they have most likely paid attention to the game). Sorry if I have missed any. List is in no particular order. Please feel free to comment with any games I have missed or broken links.

+Google Play
#achievements
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#googleplaygamesservices
#diversion

Osmos HD - https://play.google.com/store/apps/details?id=com.hemispheregames.osmos

Riptide GP - https://play.google.com/store/apps/details?id=com.vectorunit.blue

Bouncy Ball - https://play.google.com/store/apps/details?id=com.raongames.bouneball

Jewels 2 - https://play.google.com/store/apps/details?id=org.mhgames.jewels2

Beach Buggy Blitz - https://play.google.com/store/apps/details?id=com.vectorunit.yellow

Quell - https://play.google.com/store/apps/details?id=com.fallentreegames.quell

Quell Reflect - https://play.google.com/store/apps/details?id=com.fallentreegames.quellreflect

Stick Stunt Biker 2 - https://play.google.com/store/apps/details?id=com.djinnworks.StickStuntBiker2.free

Shine Runner 2 - https://play.google.com/store/apps/details?id=com.vectorunit.green

iStunt 2 - https://play.google.com/store/apps/details?id=com.miniclip.istunt2

Townsmen - https://play.google.com/store/apps/details?id=com.hg.townsmen7free

Dr. Driving - https://play.google.com/store/apps/details?id=com.ansangha.drdriving

Hills Of Glory 3D - https://play.google.com/store/apps/details?id=com.mando.hog3dfree

Save The Puppies - https://play.google.com/store/apps/details?id=com.hg.savethepuppiesfree

Quell Memento - https://play.google.com/store/apps/details?id=com.fallentreegames.google.quellmemento

Quell Free - https://play.google.com/store/apps/details?id=com.fallentreegames.quellfree

Farm Invasion USA - https://play.google.com/store/apps/details?id=com.hg.farminvasionfree

Campus Life - https://play.google.com/store/apps/details?id=com.pocketgems.android.campuslife

Coach Memory! Brain Trainer - https://play.google.com/store/apps/details?id=com.bpi.master.mm

Zuma Game - Zodiac Saga Online - https://play.google.com/store/apps/details?id=com.catstudio.zuma1

Bowling Paradise Pro FREE - https://play.google.com/store/apps/details?id=com.innolab.BowlingParadiseProFREE

Queen's Escape - https://play.google.com/store/apps/details?id=com.sonistudios.unblockthemall

Townsmen Premium - https://play.google.com/store/apps/details?id=com.hg.townsmen7

Farm Invasion USA - Premium - https://play.google.com/store/apps/details?id=com.hg.farminvasion

Rocket Island - https://play.google.com/store/apps/details?id=com.hg.rocketislandfree

Ninja Cat- Flying!! - https://play.google.com/store/apps/details?id=com.gclue.nekonin.sora

Angry Chicken: Egg Madness - https://play.google.com/store/apps/details?id=com.BlackSheepGames.Angry_Chicken_Egg_Madness

Gem Collapse 2 - https://play.google.com/store/apps/details?id=com.meyume.gemcollapse2

Pig Runner - https://play.google.com/store/apps/details?id=com.vfcosta.running

Gunslugs - https://play.google.com/store/apps/details?id=com.orangepixel.gunslugs

B.M.Snowboard Free - https://play.google.com/store/apps/details?id=goldenhammer.BMSnowFree

Quadropus Rampage - https://play.google.com/store/apps/details?id=com.bscotch.quadropus

Football Flick Tricky Shot - https://play.google.com/store/apps/details?id=com.dreamappslab.trickyshot

Gunslugs Free - https://play.google.com/store/apps/details?id=com.orangepixel.gunslugsf

JewelLife - Match 3 Jewels - https://play.google.com/store/apps/details?id=com.MBGames.JeweLife

Eyelord - https://play.google.com/store/apps/details?id=com.secretexit.eyelord

Bopbop - https://play.google.com/store/apps/details?id=com.inferno.mobile.dotdot

Quiz Just Be Smart - https://play.google.com/store/apps/details?id=com.fately.quiz.justbesmart

Blade Journey (Kung Fu Ru) - https://play.google.com/store/apps/details?id=com.drogo.bladejourney

Coach Memory! Brain Trainer+ - https://play.google.com/store/apps/details?id=com.bpi.master.mm.pro

Roll Mania Lite - https://play.google.com/store/apps/details?id=com.larfco.RollManiaLite

PBA® Bowling Challenge - https://play.google.com/store/apps/details?id=com.concretesoftware.pbachallenge_androidmarket

Secret Connection - https://play.google.com/store/apps/details?id=com.jpenza.seeksecretsolution

Personal Voice Judge - https://play.google.com/store/apps/details?id=com.fately.personal.voice.judge

Little Luca - https://play.google.com/store/apps/details?id=com.glowingpinestudios.littleluca

Ball Maze - https://play.google.com/store/apps/details?id=com.oprisnik.ballmaze

Slice HD - https://play.google.com/store/apps/details?id=hu.twofish.slice

Ball Maze Lite - https://play.google.com/store/apps/details?id=com.oprisnik.ballmazelite

BoxMan (not fully confirmed) - https://play.google.com/store/apps/details?id=com.boxman.BuBuCompany

ONLINE RPG AVABEL - https://play.google.com/store/apps/details?id=com.asobimo.avabel_gp_b3

A2Z - https://play.google.com/store/apps/details?id=pt.xenops.a2zplay

Sketchboom Squad - https://play.google.com/store/apps/details?id=com.orangepixel.spring

Bubble Shooter Cats - https://play.google.com/store/apps/details?id=com.appbasic.catbubbleshooter

Save The Puppies Premium - https://play.google.com/store/apps/details?id=com.hg.savethepuppies

Adventures Under The Sea - https://play.google.com/store/apps/details?id=com.toccata.games.adventures

Final Fantasy IV - https://play.google.com/store/apps/details?id=com.square_enix.android_googleplay.FFIV_GP

Word Slice - https://play.google.com/store/apps/details?id=com.praveen.word

Wind-Up Knight - https://play.google.com/store/apps/details?id=com.robotinvader.knightmare

Triple Town - https://play.google.com/store/apps/details?id=com.spryfox.tripletown

Hungry Monstr - https://play.google.com/store/apps/details?id=com.blowfishstudios.games.hungrymonstr

Gravity Guy Free - https://play.google.com/store/apps/details?id=com.miniclip.gravityguy

Eufloria HD - https://play.google.com/store/apps/details?id=com.omnilabs.eufloria

Chip Chain - https://play.google.com/store/apps/details?id=com.appabovegames.chipchain

Eternity Warriors 2 - https://play.google.com/store/apps/details?id=com.glu.ewarriors2

Kingdom Rush - https://play.google.com/store/apps/details?id=com.ironhidegames.android.kingdomrush

Modern Combat 4: Zero Hour - https://play.google.com/store/apps/details?id=com.ironhidegames.android.kingdomrush

Plague INC - https://play.google.com/store/apps/details?id=com.miniclip.plagueinc

Super Stickman Golf 2 - https://play.google.com/store/apps/details?id=com.noodlecake.ssg2

World Of Goo - https://play.google.com/store/apps/details?id=com.twodboy.worldofgoofull

Minesweeper 3D - https://play.google.com/store/apps/details?id=com.wiirecords.minesweeper3d

ZooKeeper Battle - https://play.google.com/store/apps/details?id=jp.kiteretsu.zookeeperbattle.google

Dino Run: Jurassic Escape - https://play.google.com/store/apps/details?id=com.basaltgames.google.lizardrun

Cyclone 2000 - https://play.google.com/store/apps/details?id=org.nocrew.tomas.cyclone2000.full

Jungle Jumper Free - https://play.google.com/store/apps/details?id=com.arnklit.games.JungleJumper

Feed The Sheep: Wooly Puzzle - https://play.google.com/store/apps/details?id=fr.hartok.sheep

Static Quest: The Delivery - https://play.google.com/store/apps/details?id=com.cookiebit.staticquest

Hyperlight - https://play.google.com/store/apps/details?id=com.CatfishBlues.Hyperlight

My Singing Monsters - https://play.google.com/store/apps/details?id=com.bigbluebubble.singingmonsters.full

BrickItOut2 - https://play.google.com/store/apps/details?id=com.werren.brickitout2

Diversion - https://play.google.com/store/apps/details?id=com.ezone.Diversion#diversion