We all know that Crystal Beast might not be the most high profile strategy and it is admittedly a pretty complicated deck requiring LOTS of game and deck knowledge to work well. Their gimmick of placing themselves in the backrow as continuous spells that do nothing other than allow their (admittedly quite powerful) backrow lineup to even be usable is pretty outdated by today's standards. (Centur-Ion for example do stuff while back there, CBs just sit patiently) Well with Supreme Darkness the Crystal Beast strategy got a second wind in the form of 2 new monsters to utilize in their extra deck:
Snake-Eyes Doomed Dragon and Clockwork Knight do wonders for this deck.
However the first question we're gonna ask ourselves would probably be: "Why would we even consider touching this deck from 18 years ago?"
The answer: "Because it is based as fuck"
Also: Crystal Beasts might have the issue of being a pretty old deck, but it aged pretty well since its main gimmick was swarming the board with small monsters that can now be used for generic Xyz and Link fodder.
The next reason: Crystal Beast Sapphire Pegasus (while capable of missing timing) does NOT have a Once per Turn clause. And the same applies for Crystal Beast Ruby Carbuncle. Our main priority is getting those two into rotation and abusing this fact as much as possible to keep out field topped up with more materials for more summons. Yet another compelling argument for Crystal Beast's ability to churn out Rank 4s: Crystal Beast Rainbow Dragon. This addition to the card pool from 2022 facilitates two things: one less bad Crystal Beast name in deck for Rainbow Dragon AND he turns any way to get to Pegasus (preferred one would be Crystal Bond since that card is basically a custom card for CBs) into a one-card Rank 4 (that dies to Artifact Lancea if you don't have any other way to extend though...).
Now as you can see, I've pretty much tried to split the decklist into some neat parts of 10 cards each with a different purpose (more visible in the deck builder but we'll manage)
Part 1: 7 Colours of the Rainbow (but fuck purple)
Here we have all the Crystal Beasts we play. Most of these that aren't named Pegasus or (debatably) Carbuncle are bricks in hand, which is why we run 60 cards in this list to reduce the odds of drawing into the one-ofs. This list does not run Crystal Beast Amethyst Cat because IMO she brings the last to the table as a level 3 with a Battle Phase effect and since OG Rainbow Dragon requires exactly 7 names, Crystal Beast Rainbow Dragon is a major blessing to us. A case can be made to cut Crystal Beast Topaz Tiger in her stead but I prefer to have the additional lvl 4 name available. The rest of the names exist to allow us a Rainbow dragon and his bigger and meaner Fusion Retrain Ultimate Crystal Rainbow Dragon Overdrive who can punch for 11k or clear the board of everything other than towers and proceed to generate the bodies necessary to OTK anyway.
Part 2: Crystallizing our engine
These cards are our main search targets for the spells in Part 3 and some of the most powerful tools that Crystal Beast has to offer.
Golden Rule is a straight up busted card that is also an equip spell. It scales up 2 Crystal Beasts from your deck and either revives or cheats out a CB monster for you to use. Especially with a Crystal Beast Ruby Carbuncle in rotation this is insane since it also proceeds to immediately special summon the scaled up Crystal Beasts so you can use them as a material for a summon or just enjoy their company. Since it's an Equip Spell we can also search for it with Power Tool Dragon in case we didn't manage to draw into it as long as 3 copies are in the deck.
Crystal Bond by itself is your full combo so of course you want to play 3 of it. Just search for Pegasus and scale Crystal Beast Rainbow Dragon and you're off to the races with your first Rank 4 (usually Springans Merrymaker unless your hand contains both Springans main deck monsters)
Awakening of the Crystal Ultimates is a fun card to extend our plays as well, granted we have a Rainbow Dragon on our field or in our hand. Crystal Beast rainbow Dragon requires us to search for OG Rainbow Dragon (or Rainbow Dark Dragon but Overdrive variants don't run him) to resolve his effect so OG Rainbow Dragon is one of the worst cards to have in our starting hand. The ability to search/dump a "Rainbow Bridge" card makes it very worth it to run it though and the Emergency Teleport of a Crystal Beast also has a tendency to come up sometimes.
Crystal Miracle is just a neat little interruption that is very searchable and as a Counter Trap very hard to respond to.
Part 3: Bridging the Rainbow
In this part we have the Rainbow Bridge cards which all have some very powerful effects that are yet another tier of custom card. The original Rainbow Bridge might seem simple but sometimes that simplicity is outright insane. Being able to search any Crystal spell is an incredibly strong effect and it is even stronger, when someone forgot to print a Once per Turn clause on it so if you have 3 Rainbow Bridge in your hand, the sky is the limit.
Rainbow Bridge of the Heart does even more for us. It allows for an additional Normal Summon of a Crystal Beast so it is a free extender. Then it can also search for a Crystal card for the lowly cost of destroying a Crystal Beast in your hand or on your field. AND THEN it also allows you to bounce something (and itself) when a Crystal Beast gets placed in your backrow (something that you can control pretty well and will do quite often)? If it only had any 2 of those effects it would still get played. The bounce effect is very nice to out some floodgates (only one we kind of suffer under is Anti-Spell Fragrance but for that we can still side in Lightning Chidori which we can make with Pegasus and Crystal Beast Cobalt Eagle which even works under There Can Be Only One and Gozen Match )
And last but not least: Rainbow Bridge of Salvation. We genuinely don't care about the regular trap effect. What we do care about is getting it into our graveyard. At that point we can banish it to search a Pegasus and any field spell (Necrovalley and Kyoutou Waterfront (which in turn gets to search for Gameciel, the Sea Turtle Kaiju that can be summoned by a 3+ mat Saryuja Skull Dread for semi-infinite negates in the case of this list) For the purposes of getting Salvation into our graveyard we run a playset of Foolish Burial Goods and some other goodies.
Part 4: Pouring my Souls into these crystals until I can't (Shield-)bear it anymore
This part is comprised of some more consistency tools and payoffs for Salvation.
Magicians' Souls can easily be summoned by milling Illusion of Chaos (which can search for Souls and either put itself or a Rainbow Dragon back into the deck to turn Crystal Beast Rainbow Dragon back on) and Souls gets to send up to 2 spells/traps from your hand/field to the grave to draw as many cards. This doesn't just allow us to slightly unbrick our hand when we draw too many board breakers, it also allows us to send Crystal Beasts from our backrow and Salvation from our hand to the grave to extend even further beyond.
Noble Knight's Shield-Bearer is a curious case of pure consistency since it can discard itself for a search of Pegasus. (This is one of the first things to side out for anything though IMO)
Part 5: Is this still Crystal Beast?
The fifth part contains the Springans engine which we can use to make a 4 mat Saryuja, a Power Tool Dragon (into Crystal Wing Synchro Dragon ) to search for Golden Rule and the Nemeses package which facilitates Thunder Dragon Colossus for the low cost of 2 banished monsters.
Nemeses Flag is searchable by Infernal Flame Banshee which is completely generic to make with two lvl 4s. In addition Flag is capable of searching Nemeses Corridor (or Archnemeses Protos if you side him in for matchups against DARK decks). Both Nemeses monsters are pretty much free to summon as long as you have a banished monster. Crystal Beast Rainbow Dragon is usually one of the targets. The other can be either something you banish yourself with S:P Little Knight or something your opponent banished from you (E.g. a Ruby Carbuncle that got hit by a Bystial since it's a LIGHT...)
The Springans are relatively self explanatory. Springans Pedor and Springans Brothers are the new favorite ones to main deck because the have less than 1000 ATK, making them eligible materials for Clockwork Knight. Tally-ho! Springans is our primary search with Gigantic "Champion" Sargas which we can just put on top of Springans Merrymaker. Tally-ho! then allows us to summon all 4 Springans to our field and extend from there. Now for the SPICE in this combo:
If we have a Crystal Beast in our backrow at this time (usually Carbuncle), we can use one of the lvl 4 Springans to summon Clockwork Knight and send the Crystal Beast to the graveyard and search Clockwork Night. The on-field effect of Night doesn't matter to us but we like to see it in our graveyard. So then we get to use Knight's second effect to tribute Merrymaker and summon the Springans that was used as a material for Knight and overlay for another Rank 4 (like Banshee). When we use Banshee's effect to search a Pyro, we get to use Sargas' effect to either bounce or destroy a card on the field so we can destroy Night to gain access to its grave effect which in turn can search for Revolution Synchron for the cost of a discard. We then summon Nemeses Flag that got searched by Banshee, search for Corridor. Sargas + Knight for Cross-Sheep, Flag + Banshee for S:P Little Knight to banish another card so we get to summon Nemeses Corridor and use him + Revolution Synchron in Hand for Power Tool Dragon to search Golden Rule. Then revive Revolution Synchron to use him and Power Tool for a Crystal Wing.
Therion "King" Regulus is in here as another semi-generic negate option when we have already drawn into Tally-Ho or Revolution Synchron to search off of either Sargas or Night.
Part 6: Nice board you have there. Would be a shame if someone were to break it
Regular non-Engine. The deck has at least 13 spots open for whatever non-engine you prefer to run but it really shines with board breakers. If you prefer to go first I'd switch some cards in the main deck for a Crossout Designator package though since we're susceptible to basically any hand trap...
Extra Deck: The Extra Deck is kind of self-explanatory for an Overdrive Turbo list and some other parts were discussed further up. Saryuja Skull Dread is awesome at fixing our hand and extending our plays. And when he did his thing we can use him for Worldsea Dragon Zealantis who is capable of retriggering our Pegasus und Carbuncle effects on the field. (So if you control 2 Pegasus and one Carbuncle with Zealantis and another monster you get to scale up 2 more Crystal Beasts from your deck. If you have a zone open at that point you even get to summon another CB to your board.
Thunder Dragon Colossus can be summoned during a turn you summoned Nemeses Corridor using its own effect by tributing Nemeses Corridor. If you use the combo I talked about during the discussion of Part 5 you'll need to revive it somehow though (best case for that is Cross-Sheep shuffled back with Daigusto Emeral)
And for the real MVP of this deck: Snake-Eyes Doomed Dragon. I haven't talked about him a lot yet. HOWEVER he is doing a LOT for us. He can be summoned by using 2 Spells/Traps that are originally Monsters and sending them to the Graveyard and as a Fusion monster he also procs Cross-Sheep's revive effect. He's basically a free summon that puts more CB names where they belong (in the bin).
Now the final slot of Knightmare Gryphon is pretty much a flex spot. He's a nice floodgate that prevents non-linked monster effect activations but we can make a case that a Tower like Five-Headed Link Dragon or a hard to out board breaker like Underworld Goddess of the Closed World can take up that slot. Or maybe even something simple like Firewall Dragon with more generic materials and a bounce as interruption (The Apollousa, Bow of the Goddess ban in the TCG really hurt tbh but we manage I guess).
The Side Deck contains a few more cards you can also either consider running in the deck or are just good to have in the side in general like Lightning Chidori as an out to stun, Number 41: Bagooska the Terribly Tired Tapir as the last resort end board or Archnemeses Protos as an alternative way to floodgate your opponent.
Obviously I'm not an OG Crytal Beast cook like for example Dread Guy on Youtube (if you want to learn the deck I can only urge you to check out his videos, this man is a savant with this deck) but I am trying to increase the range of it