The "Frog Engine" is one of the best deck engines for Tribute Summons, especially the "Monarchs". It consists of the following cards. This deck engine used to be extremely powerful because of "Substitoad". However, it is currently Forbidden.
The engine works by discarding a WATER monster to Special Summon "Swap Frog". Then you can use "Swap Frog's" second effect to send a Level 2 or lower Aqua-type monster to the Graveyard (preferably "Treeborn Frog" or "Ronintoadin"). If you sent a Treeborn Frog to the graveyard, on your next Standby Phase, you can special summon it and use it for a tribute of your choice, or if you sent Ronintoadin instead, and you already have other Frogs in the graveyard you can immediately special summon Ronintoadin and use that for the tribute of your choice.
You can also take advantage of this deck's almost endless supply of tributes by using cards such as "Enemy Controller" and "Creature Swap" in addition to your Tribute Monsters to stop Synchro Summons or to take one of your opponent's monsters and in return give them a monster with 100 ATK.
Your weaknesses include cards that stop tributes such as "Mask of Restrict".
Different Dimension Decks and Bounce Decks can also hinder you because of the engine's use of the Graveyard and your level 5 or higher monsters being sent back as soon as they are summoned.