Main Deck:
Rikka Petal: Good with One for One, helps search out Rikka cards on your Main Phase. Also good for special summon fodder. Pairs well with Lonefire for basically infinite tributes (almost).
Snowdrop the Rikka Fairy: Use her to get more plant monsters on the field. Very good for Link fodder and XYZ fodder. Also a good boss.
Erika the Rikka Fairy: Plant support discards itself upon attack against another Plant monster you control, adding 1000 ATK/DEF until end of turn. Pretty good with other Rikka cards that require tributes. Also pairs well with
Lonefire Blossom to summon itself.
Mudan the Rikka Fairy: A searcher for Rikka spells and traps like Rikka Tranquility. Good for this deck in specific. Pairs well with Evil Thorn to summon it from your hand.
Cyclamen the Rikka Fairy: Basic special summon XYZ/Link fodder. Helps reduce level by 2 for XYZ.
Primula the Rikka Fairy: Basic special summon XYZ/Link fodder. Helps increase level by 2 for XYZ.
Traptrix Genlisea: Use to get out the traps first turn if possible. You want to go first with this deck. Pair with Dionaea late-game to get out more traps on the field.
Traptrix Myrmeleo: Used to get "Hole" Trap Cards in your hand pretty fast. Pairs with Dionaea. Run more Dionaea if you want to run more Traptrixes in your deck rather than Rikkas.
Traptrix Dionaea: Used to Special Summon monsters, specifically Traptrix ones, from your GY. Also helps get recovery traps from GY. Pair with Myrmeleo to clear traps and spells, or pair with Mantis to search for Myrmeleo and get traps to your hand.
Traptrix Mantis: Used to search Traptrix. Basic card, 2nd effect helps save traps with a Quick Effect. Also good for setting down traps you want to use later.
Lonefire Blossom: Pairs with basically every single monster. Good card.
Evil Thorn: Pairs with itself and Lonefire Blossom as tribute fodder. Good for links as well because it summons itself up to 2 extra times.
One for One: Searches for Rikka Petal.
Bottomless Trap Hole/Deep Dark Trap Hole/Time Space Trap Hole/Traptrix Trap Hole Nightmare/Void Trap Hole: Will help you immensely in destroying some setup monsters and strong monsters. If you prefer Torrential Tribute (with Fury of Kairyu-Shin) or Grand Horn of Heaven, that is totally okay too because it works well with Rikka cards.
Trap Trick: A go-to setup for Hole cards.
Extra Deck:
Teardrop the Rikka Queen: Very good card to clear your enemy's field and make them cry.
Kanzashi the Rikka Queen: Protection for plants.
Traptrix Allomerus: Good for taking your opponent's monsters and also for Traptrix Support. Gets Traptrix cards from the GY onto the field.
Silent Honor ARK: Good for taking your opponent's monsters. Fun card. Works with Traptrix cards.
Rikka Queen Strenna: Works with Traptrix to summon a higher Rikka monster and gives it more materials. Very funny.
Traptrix Rafflesia: Works with Traptrix to get more Hole cards (essentially) by sending them to the GY. Makes them a Quick Effect.
Saryuja Skull Dread: Generally helpful with Special Summoning and such. Also (essentially) mulls your hand without having you discard. Good in general but not exactly the optimal play.
Traptrix Sera: Great Traptrix support, helps get out a ton of different Traptrix every time you activate a Normal Trap.
Side Board:
Break-Off Trap Hole: Link support. Helps that the Traptrix cards are unaffected, essentially making it a Raigeki.
Floodgate Trap Hole: Disables the enemy and cripples their monsters.
Mirror Force: The reason I have trust issues. A very good card. Could be a win condition.
Rikka Sheet: Takes control of their monsters. Good for Link fodder.
Rikka Tranquility: Summons 2 plants from your GY if done right. Have 1 on your field to make it work.
Storming Mirror Force: For when Mirror Force is no longer valid.