1x Roon of the Hidden Realm
1x Acidic Slime 1x AEther Adept 1x Agent of Treachery 1x Altered Ego 1x Angel of Condemnation 1x Brago, King Eternal 1x Bramble Sovereign 1x Brutalizer Exarch 1x Coiling Oracle 1x Deadeye Navigator 1x Duplicant 1x Eternal Witness 1x Farhaven Elf 1x Flickerwisp 1x Gilded Drake 1x Hornet Queen 1x Lavinia of the Tenth 1x Manglehorn 1x Meteor Golem 1x Mistmeadow Witch 1x Phyrexian Ingester 1x Prime Speaker Zegana 1x Risen Reef 1x Reflector Mage 1x Restoration Angel 1x Riftwing Cloudskate 1x Seedborn Muse 1x Solemn Simulacrum 1x Soulherder 1x Stonehorn Dignitary 1x Thassa, God of the Sea 1x Vedalken Plotter 1x Venser, Shaper Savant 1x Woodfall Primus
1x Arid Mesa 1x Command Tower 1x Flooded Strand 4x Forest 1x Glacial Fortress 9x Island 1x Lumbering Falls 1x Misty Rainforest 1x Path of Ancestry 3x Plains 1x Polluted Delta 1x Reliquary Tower 1x Savannah 1x Scalding Tarn 1x Seaside Citadel 1x Tropical Island 1x Tundra 1x Wooded Foothills
1x Cyclonic Rift 1x Eerie Interlude 1x Force of Will 1x Ghostway 1x Illusionist's Stratagem 1x Momentary Blink 1x Pull from Tomorrow 1x Radiant Purge 1x Return to Dust 1x Sphinx's Revelation
1x Aura Shards
1x Venser, the Sojourner
1x Commander's Sphere 1x Conjurer's Closet 1x Darksteel Ingot 1x Everflowing Chalice 1x Illusionist's Bracers 1x Lightning Greaves 1x Mind Stone 1x Obelisk of Bant 1x Panharmonicon 1x Pristine Talisman 1x Sol Ring 1x Swiftfoot Boots 1x Talisman of Progress 1x Talisman of Unity 1x Thran Dynamo 1x Vedalken Orrery
1x Braingeyser 1x Explosive Vegetation 1x Mind Spring 1x Skyshroud Claim 1x Traverse the Outlands
Bounce based control deck. Ramp up to as much mana as you can early on, you will need it. Roon is a mana hungry deck. Be sure to play as much lands as possible by bouncing Risen Reef, Coiling Oracle, Farhaven Elf, and Solemn Simulacrum. Traverse the Outlands should be cast for at least four lands, preferably more than five.
Once you have enough mana to work with, start casting and bouncing board disruption ETB Creatures like Manglehorn, Lavinia of the Tenth, Phyrexian Ingester, Duplicant or Meteor Golem. Try to keep Roon of the Hidden Realm protected with Hexproof equipment if possible. Manage your resources, draw spells, and bounce effects to make sure you always have a full hand of cards and that mana is available to bounce creatures in response to removal.
Once you have enough pieces out like Panharmonicon, Conjurer's Closet, Seedborn Muse, or Brago, King Eternal, you can begin to soft lock players into not being able to advance their boardstate. Re-use ETB effects as many times as you can. Venser, Shaper Savant becomes a re-usable bounce and counterspell. Gilded Drake will return to the battlefield under your control when bounced and will retrigger. Vedalken Plotter can be used to steal powerful lands or simply disrupt an opponents mana base by locking them out of a color.
Bouncing any of these creatures enough times will usually result in a hard lock / win: Brutalizer Exarch, Woodfall Primus, Acidic Slime, Woodfall Primus, Riftwing Cloudskate, or Agent of Treachery. Deadeye Navigator should usually be saved until you have enough mana to pay for multiple triggers on the same turn you cast it.
If you can't establish a lock with the bounce effects, chip away at your opponents health with any creatures you can. Roon of the Hidden Realm can make an excellent attacker and has both Vigilance and Trample. Learn the nuances of Roon's tap ability for bouncing creatures out of combat or bouncing them in response to a removal effects.