This is my take at a "Gladiator Beast" deck. Originally, "Gladiator Beasts" were a battle-focussed archetype with a unique gimmick which is referred to as "taging out", in which a "Gladiator Beast" monster could shuffle itself into the deck after being part of a battle and summon another "Gladiator Beast" from the deck which would then activate some sort of effect. They still have this ability and work with it, but the more modern support also gave them ways to tag without even attempting a battle while providing the deck with various other cards and strategies to make use off.
First and foremost, the Normal Monster in the archetype in form of "Gladiator Beast Andal" is absolutely crucial. Unlike various other archetypes that have Normal Monsters in their ranks, "Gladiator Beast Andal" is a solid beater, can be used for various other summons in the deck and is a consistent Special Summon to use via "Rescue Rabbit" and "Unexpected Dai".
The Effect "Gladiator Beast" Monsters I run are one copy of "Gladiator Beast Attorix", both for the graveyard setup as well as her ability to change her level in order to be used for certain Fusion monsters, two copies of "Gladiator Beast Bestiari" for his backrow removal effect and because he is of paramount importance to summon "Gladiator Beast Gyzarus" from the Extra Deck, one copy of "Gladiator Beast Equeste" for the very useful ability of recycling "Gladiator Beast" Spells, one copy of "Gladiator Beast Darius" for an in-archetypal "Monster Reborn", one copy of "Gladiator Beast Noxious" for yet more graveyard setup, the effect of preventing one attack with the added bonus of being able to tag during the opposing turn, one copy of "Gladiator Beast Vespasius" as more high-level Fusion material that can Special Summon itself and two copies of "Gladiator Beast Augustus" for yet more high-level monster for the Extra Deck summons with the added bonus of being able to swarming the field with "Gladiator Beasts" and also triggering their effects since they still get summoned correctly. The generic monster options aside from "Rescue Rabbit" are three copies of "Test Tiger", which are more swarming and allow more hands you draw to go into "Test Panther" and three copies of "Ash Blossom & Joyous Spring" for interruption that you can and should absolutely afford to play.
The backrow has three "Unexpected Dai" for "Gladiator Beast Andal", three "Gladiator Beast's Comeback" for various reasons but mostly as a play extender, three copies of "Gladiator Proving Ground" as the "Reinforcement of the Army" for "Gladiator Beasts", one "Mind Control" to clear monsters off the opposing field while also gaining material for "Test Panther", "Pot of Avarice" to make "Gladiator Beast" monster available again which allows you to activate cards like "Rescue Rabbit" and "Unexpected Dai" again, one "Gladiator Beast United" to surprise opponents during the Battle Phase by summoning monsters such as "Gladiator Beast Domitianus", three copies of "Gladiator Rejection" as a useful summoning tool and a way to give your monsters targeting protection, one "Gladiator Beast Charge" as a board clear, one copy of "Gladiator Beast War Chariot" as a searchable anti-monster effect Counter Trap and lastly one "Double or Nothing!" for the well-known "Utopia Double" engine.
In terms of the Extra Deck "Gladiator Beasts" actually use quite a lot of the options they have at their disposal. "Gladiator Beast Essedarii" is only in the Extra Deck to have access to another Level 5 "Gladiator Beast" monster if I have enough option in the Level 4 segment but cannot go any higher with the available cards. The aforementioned high-level "Gladiator Beasts" are absolutely necessary as you pretty much always want to summon "Gladiator Beast Tamer Editor", who pretty much summons Extra Deck monsters for free and therefore really pays for himself. Options to summon via "Gladiator Beast Tamer Editor" include "Gladiator Beast Heraklinos" for as many Spell/Trap negates as you want as long as you can pay for it by discarding cards from your hand, or "Gladiator Beast Domitianus" who comes with 3500 ATK, can negate a monster effect per turn and lets you choose what the opponent has to attack. Equally as important in the Extra Deck is the aforementioned "Gladiator Beast Gyzarus", who gets rid of two opposing cards when summoned. Constantly resummoning "Gladiator Beast Gyzarus" is something that is relatively easy in this deck and can clear the field while you are still setting up for an OTK scenario. The main play enabler is "Test Panther", who is summonable with two monsters of which thankfully only one needs to be a "Gladiator Beast" monster, and it fetches "Gladiator Beast" cards on summon while also allowing to "tag out" without the need of an attack. The rest is pretty straightforward: I run the two cards necessary for the "Utopia Double" engine, one "Borrelsword Dragon" since it supports the beatdown strategy really well, "Knightmare Phoenix" against opposing backrow, one copy of "Gladiator Beast Dragases" for the rare scenarios in which he is a better choice than "Test Panther" and one "Link Spider" to make the best out of two copies of "Gladiator Beast Andal" in your starting hand.
I only started writing about "Gladiator Beasts" after a friend of mine asked me to help him build a deck with them, but after I was finished going through them all I had to admit that they are an interesting bunch of cards to work with. I feel like they run out of resources rather quickly but they do perform quite well with some explosive plays while also staying true to their archetype's identity. If you want some more information on "Gladiator Beast", for example about the cards I left out in this 50+ card archetype, then feel free to take a look at my archetype analysis on my blog: https://cubiccreativity.wordpress.com/2020/12/19/archetype-analysis-gladiator-beast/.