Dinosaur is one of, if not, my favourite monster types in the game. Unfortunately, there exists no good Dinosaur strategy in the current format. The most success a Dinosaur-centric deck had in the entire lifespan of Rush is with Great Imperial Dinocarriage Dynarmix, a maximum monster. While back then the ability to not be destroyed by Level 7 or lower monsters and the ability to repeatedly clear monsters every turn was incredibly strong, nowadays decks can make big boards very easily, and outs to maximum monsters are both more plentiful and more easily accessible. As such, Dynarmix, as with most Maximum monsters, fell to the wayside. It also doesn't help that Maximum strategies benefit from a slower game, getting more time to find their pieces, but the current format is fast and explosive, creating an inconducive enviroment for them. As someone who had been trying to make some semblance of a competitive Dinosaur list, it was incredibly difficult to make work, especially with many popular competitive decks inherently having maximum outs. This was a clear sign to go back to the drawing board, especially since I had never been too fond of Maximums in the first place (If you want to play with Dynarmix your best bet is to run it in WMax, though the maximum slots there could be literally anything and there are better options).
There exists 3 other high level Dinosaur monsters to build around. Zenigebazauls, which is atrociously bad, Super King Rex, which didn't provide anything particularly unique, except for access to the 3rd option, Hyper Upstart King Rex. Hyper is a Fusion Monster, meaning that a good portion of the deck has to be dedicated to the spell Fusion, which is unfortunate but it's not like the other options are particularly exciting. Unfortunately, this card also comes with its host of problems. Firstly, its fusion materials aren't easily recoverable. While Normal Monsters can be recovered through Star Restart, neither of the fusion materials are normal monsters. Secondly, while the effect of retrieving any spell you want from grave is alluring, it's locked behind having an Upstart Goblin in grave, one of, if not, the weakest Legend cards available. While the card is technically usable without the spell recycling effect, there'd be no point in playing this deck at that point, and as such we're forcing it in. Silver lining is it gives additional value to Upstart King Rex, which can reset it onto your field upon activation. Finally, the payoff is completely overshadowed by Magical Stone Excavation. While admittedly it costs 2 cards, it is not only generic but also not locking you to a bad legend card, allowing you to reuse powerful cards like Secret Order and even legends like Monster Reborn a lot easier than jumping through a million hoops with Hyper Upstart. We didn't make this deck with the intention for it to be a competitive threat though, so we're powering through anyway.
With that preamble out of the way, lets talk about the cards. As for 2 tribute monsters, We're not running many of them both because of space and because the big beaters should theoretically come from Fusion. 3 copies of Super King Rex are mostly here because its fusion material, but it also provides some interesting niches. It being able to recycle lower level nomal Dinosaurs means that it can grab Gracesaurus, which we're playing 3 of, another material for a different fusion, Metallion Ladonstar. This allows us to set up for Ladonstar, and even aim to make 2 fusions in 1 turn if the stars align. We're also playing 1 Megazowler as the biggest target off of Super King Rex, being Level 6 is also important but we'll go over that later. Draw power is quite important if you're looking to make multiple fusions, and as such we've chosen Trade-In as filtering in spell form. Ideally Ship of Seven Treasures would be better, however Super King Rex is a Level 8, and with the already low number of main deck bosses we plan to run, Ship is a no-go. Running 2 copies of Trade-In means that we'll be finding more Level 8s to run. I've chosen 3 Ecdysis Caliguleon as a beater that gets big numbers to help in beating over things. Yamiruler the Dark Delayer is another option, however another 2 tribute that doesn't beat over 2.5ks would be somewhat risky in the format where decks can easily spam 2.5k bodies. As for the final 2 tribute, we're playing 1 Royal Rebel's Heavy Metal. This is really a flex slot and can be anything, but is strongly suggested to be a Level 8. Heavy Metal plays well with the Megazowler in the deck, where you can special Megazowler off of Super King Rex and tribute Megazowler and some other low level for Heavy Metal and its effect (you could also tribute the Super King Rex itself but ideally you get to keep the 2.5k beater and fusion material).
Alongside 3 Gracesaurus, our low levels also consist of 3 Upstart King Rex, the other material for Hyper, 3 Imaginary Actor, the other material for Ladonstar, and 2 Sword Dancer, the fusion material, alongside Actor, for Metallion Asurastar, providing an alternate fusion option. Despite being forced to run Upstart King Rex, the card is already quite good, being extra draw power, so it's nice to be running it anyway. As for other consistency tools, 3 Amazing Dealer is extremely welcome here, very strong consistency tool in many decks. It also happens to have a fusion in Splendid Floor Master, which normally is irrelevant but we happen to be playing a fusion deck, so might as well remember it exists. 3 The Strange Specter of Celestial Severance is very strong in this kind of deck. We want to find many things in grave, Super King Rex targets, Upstart Goblin (better than actually activating the card), recycle options for Hyper, Star Restart targets to name a few. Celestial Severance, allowing us to pick which of the top 3 we want in grave, allows us to curate the grave to our liking. For utility we've got 3 Sea Dragon Knight. The deck doesn't have any backrow removal outside of Asurastar, so it's good to be able to check backrow without having to go into a fusion. It also recycles certain cards we want back in deck and slows down deck out.
Now for the spells. Outside of the prerequisites Fusion and Upstart Goblin, which we are on 3 and 1 of respectively, and the aforementioned 2 Trade-Ins, we're also running 1 Star Restart. You can definitely run more, but I chose to cut it down to 1 copy for space reasons. Yokai Tiger Orient Strike and Heavenly Revelation are 1 of techs as options to grab off of Hyper Upstart King Rex's full effect. As such, those can be any spell you want, like more copies of Star Restart or things like Back Beat or Hammer Crush. Orient Strike was chosen as a potential strong debuffer and/or removal spell, and Heavenly Revelation was chosen to revive your boss monsters like Caliguleon (although unable to revive the Level 9 fusions). It also synergises well with Super King Rex and Megazowler, similar to with Heavy Metal. Finally, for the traps, 1 each of Dinomic Pressure, Trap Lid and Crisis at the Sacred Tower. All of these are strong traps, Dinomic Pressure allowing you to win combat, Trap Lid punishing special summons from grave and Crisis at the Sacred Tower punishes tribute summoning. You can experiement with your own ratios here, one thing I would suggest not to do is to run more Dinomic Pressures, unless you plan on trying to fit in more Dinosaurs.
Is the deck competitive? Not by a long shot. The strategy is piece reliant and slow, and its main gimmick is overshadowed by a generic spell. Is it the strongest Dinosaur focussed deck? Unfortunately probably. The build may not be 100% perfect, but it is at least able to do something cool sometimes. If you're looking to play with dinos, this is probably the deck for you, even more so if you really don't want to touch maximums.