There's a decent monster that'll make Diamond Dude effect less random.
Big Eye
Dark Fiend 4 star
1200ATK 1000DEF
FLIP: See the 5 cards from the top of your Deck, arrange them in any order desired, and replace them on top of the Deck.
Yeah, that and Pigeonholing Books of Spell can definately help.
Just make Diamond Dude or ROTA your next draw and place a good normal spell card right under it.
Some "game breaking effects" when I searched.
#1: "Destroy all cards on your opponent side of the field" NOTE: They don't bust tokens.
Des Croaking
Mega Ton Magical Cannon
Ojama Delta Hurricane!!
#2: "Destroy all monsters on the opponent side of the field" These include Tokens.
Burst Stream of Destruction
#3: "Select 1 Spell Card from your Deck and Set it on your side of the field. You cannot use that Spell Card this turn."
Ancient Gear Drill (Since discarding is "part" of the activation requirement, it's ignored as well when using Diamond Dude according to the effect and thus no discard cost
)
#4: "Destroy all monster cards on the opponent side of the field" They don't include Tokens.
Chaos End
#5: "Destroy all Spells and Trap cards on the opponent side of the field"
Dark Magic Attack
-------------
From what I searched, Burst Stream of Destruction is better then Chaos End
But yeah, just throw in 3x Ojama Delta Hurricane! or something and that'll be better.
And since there's gunna be "Draw" probs, it's probably a very good idea to put Magical Mallet or Reload. (Probably Magical Mallet since that's a normal spell card. And your probably gunna be picky and just choose 1 or 2 bad draws back to deck anyway.)
And monsters like Helping Robo for Combat or even Maharaghi can help. (Just activate somekinda shuffling effect after Helping Robo for Combat)
Maybe even A Feather of the Phoenix to reuse the effect of good normal spell card.