Evilswarm Mandragora - Plants FTK
The combo consists of using Phoenixian Cluster Amaryllis effect during the End Phase, to Special Summon it to a zone Topologic Bomber Dragon points to, in order to destroy it, and use its effect to summon it again by banishing a plant monster, inflicting 800 LP damage to one of your opponents. With 30 monsters in your graveyard, you can kill the 3 other players at full life.
The deck consists of multiple plant archetypes to special summon and send to the graveyard as many monsters as possible. I decided to make a list 100% focused on the combo, so there are very few cards that interact with the opponents' board, and I decided to cut most of the cards that lock you into only summoning plants (the only exception being Rikka Konkon).
For the Deck Master, I decided to use Evilswarm Mandragora, for its ability to be special summoned multiple times in a turn, as long as an opponent has more monsters on the field than you. The domain of Plant and Dark monsters seems like the best option for this combo. Another Deck Master option is Predaplant Ophrys Scorpio, which guarantees Tearlaments Kitkallos, but uses your normal summon and doesn't allow for some of the plays only possible because of the recurring nature of Evilswarm Mandragora.
Some interesting points to highlight are: You can summon Tearlaments Kitkallos and mill 8 summoning Tearlaments Merrli, by summoning Predaplant Ophrys Scorpio, Predaplant Darlingtonia Cobra, and Instant Fusion. Every effect like Monster Reborn with Lonefire Blossom in your graveyard is the same as any plant from your deck. You can summon Meliae of the Trees with Sylvan Dancepione, pointing to any two earth monsters (this works well with the sunseed cards). Chaos Ruler, the Chaotic Magical Dragon works very well with the Sylvan cards to mill even more.
Playing Defensively
You won't always be able to combo on your first turn. If your opponents set up a lot of interaction on their turns or are planning to team up against you, it can be a good idea to pass on a less intimidating board and try to deal with them when they have less life and have used some of their resources against each other. For these scenarios, I added two cards that will help a lot, while not using your resources and generating card advantage: Rikka Konkon and Child's Play.
Rikka Konkon locks you into plants, so only play it if you decided you don't want to combo with Topologic Bomber Dragon. You can use this card with Rikka Glamour, which becomes the best removal in this deck. It Tributes an opponent's monster for cost, not targeting it, while you also get a Rikka monster and another plant with the same level from your deck. So, you'll remove a big threat and end up with more resources than before activating the card.
Child's Play will allow you to search for up to 3 plants from your deck during the turn cycle, by using the effect of Aromaseraphy Jasmine. If you have Aromage Jasmine, you'll also draw 3 cards. Another option that also fulfills the same role is Blessed Winds. Your opponents might be afraid of letting you search for any plant every turn, but you're happy to see they using their interactions because you'll have an easier time trying to combo during your turn. They may have other worse problems to deal with, too.
An example defensive "combo", considering that at least one of your opponents has 2 monsters on their field: Special Summon Evilswarm Mandragora, normal summon any plant from your hand, link summon Aromaseraphy Jasmine, and send Evilswarm Mandragora to the Deck Master Zone to special summon it again by paying 500 LP. Activate Aromaseraphy Jasmine effect to tribute Evilswarm Mandragora, sending it back to the Deck Master Zone. At this point, you can choose between Mudan the Rikka Fairy for the Rikka Konkon play, or Aromage Jasmine for the extra card draw. Then you can link summon Aromalilith Rosemary using the special summoned monster (or Evilswarm Mandragora if one of your opponents has 3 monsters on board), adding Aroma Blend and activating Blessed Winds. During your turn, you can activate Blessed Winds to special summon Aromaseraphy Jasmine from the graveyard. At this point, you can activate Aromalilith Rosemary's effect by summoning Evilswarm Mandragora again and adding another plant from your deck to your hand (this is also your 3 summon, so Aromalilith Rosemary's life gain effect will "cancel" the 1000 LP summoning life cost). During your opponents' turns, you can use Blessed Winds to both add more plants to your hand and protect your monsters from banishing effects.