Okay, so I made this deck a while back and figured I should share it somewhere. This is a fairly consistent FTK that abuses Superancient Deepsea King Coelacanth, which I have thought for a long time is strong enough to be banned, so I set out to find a way to break it, and I think this is it. There is just so much about this deck that happens to work out so perfectly, it's honestly kind of crazy. The FTK goes like this:
-Get any 2 level 4 monsters on the field with a Coelacanth in the grave (Leaffish does this, as well as a discard of Coelacanth to summon White Stingray, or Foolish. Summoner Monk does this by itself if you summon Leaffish.)
-Make Dugares and Summon Coelacanth
-Activate Coelacanth summoning specifically Gluttonous Reptolphin Greethys, a Royal Swamp Eel, and any other 2 Level 4s.
-Summon Halq, bring out your Lv 1 Dark Dragon tuner (specifically Dark Dragon, the Rokket one works too), and synchro with Coelacanth to make Beelze in either the leftmost or middle main monster zone (important for Geonator Transverser.)
-Link Halq and one of the 4s to make Geonator Transverser so that it points to Beelze
-Use the Reptolphin and the last Lv 4 to make White Aura Monoceros to bring back Coelacanth
-Activate Coelacanth again (yes, it's a soft once per turn) and summon a Royal Swamp Eel and Beautunaful Princess
-Make Garden Rose Maiden and search Black Garden and Activate it
-Overlay Monoceros and Coelacanth, who are both 7s, to make Red Eyes Flare Metal Dragon, which will trigger Black Garden. Put the Token into the other Geonator Transverser Zone.
-Switch control of Beelze and the Token, then link the token for Link Spider.
-Link away Transverser, Garden Rose Maiden, and Link spider for Agave Dragon, which will burn for 100 because of the Dragon Tuner you used to make Beelze, triggering the Beelze/Flare Metal interaction which will FTK your opponent.
I haven't actually played this deck in any super competitive format, so I don't know how good it actually is. I have Crossout and a few garnets for it since after the FTK tools the deck space is pretty free. I think in theory this deck is insane, so try it out sometime, but like I said, I haven't actually played it in a competitive environment.