Theorycraft: Most Game Breaking R.A.W Legal Combos

I'm curious what the most game-breaking combos that are RAW legal for players, and don't require homebrew, specific magic items, or rolled stats.  This is theory-crafting, and my example below isn't anything that I would ever expect to be allowed at any gaming table, but I find it fun to come up with.  I'm curious what utterly ridiculous game-breaking combos you've all come up with.  If your combo is 5e, 5.5, or a mix of both, please specify.

The One-Man-Army: which can gain endless reinforcements instantly at the start of a combat without needing to use any sort of action to call for them. 

Summary of Mechanics: A small team of Simulacra observing the original caster through their Homunculi which are with the original caster, and that small team is being observed by millions of other Simulacra through their Homunculi which are with the small team.  So when the original caster might be in danger, the small team alerts the rest who then teleport to the original caster en masse, without the original caster needing to do or say anything.

The build requirements:  L17 Order of Scribes Wizard, Witherbloom Student Background, the Cartomancer feat, and knowing the "Wish" and "Teleport" spells.  (This was designed for 5e)

Preparation: 

1st day: You use Hidden Ace from the Cartomancer feat to cast Wish to replicate the Simulacrum spell to create a duplicate of yourself.  Wait until you've taken a Long Rest, when you and your Simulacrum have regained your use of the Hidden Ace feature (This feature does RAW refresh for Simulacra, because it is not hit points or a spell slot) to bank a casting of Wish, to replicate the Simulacrum spell.

2nd and Subsequent days: Each Simulacrum uses its first day having Wish banked with the Hidden Ace feature to replicate the Simulacrum spell to make a duplicate of the original caster, and every six seconds the new Simulacrum does the same.  Make sure each Simulacrum is ordered to follow your instructions as if you were its creator. That's 14,400 Simulacra created on day 2, which is more than 5.25 million if you stick around and have your Simulacra create more of you for a full year. That's about 657,000 Strike Teams at your beck and call.

Each Simulacrum uses its second day of having Wish banked with the Hidden Ace feature to replicate the Create Homunculus spell to create a Homunculus for itself.  Each Simulacrum banks Wish with the Hidden Ace feature on subsequent days.

What to do with the Simulacra and Homunculi:

Recon Team: Have a group of 8 Simulacra that go to any location you plan to visit ahead of you, thoroughly scout the area, using Familiars and Awakened Minds to ensure it's safe.  Before one of them uses the Hidden Ace Feature casting of Wish to replicate Sending to tell the original caster that the area is secured, another one of them will collect materials to serve as the "associated objects" for any Teleport spell to this location, and then use its own Hidden Ace Feature casting of Wish to replicate Teleport to take said materials to the "Hall of Homunculi" (detailed below).  When you've been informed that the area is secure, you then proceed with your Security Team to it for whatever you were going to do.  The Recon Team's Homunculi are with the Security Team.

Security Team:  Have a group of 4 Simulacra that travel with you as bodyguards, Their job is 100% defense, to prevent you from coming to harm, and healing any damage that gets through their defenses.  They'll make sure you always have Death Ward cast on you, and they also have Revivify if things go seriously wrong.  They can can also use Teleport to get you and allies to safety.  The Security Team's Homunculi are with the Recon Team.

Strike Teams: Groups of 8 Simulacra that have Wish or a L9 combat spell banked with Hidden Ace, so they can pop in whenever is needed.  They can be stationed anywhere on the plane,  any continent, any city, but will as a group return to the Hall of Homunculi when called, using one of their Hidden Ace Wishes to teleport there.  Their Homunculi are already in the Hall of Homunculi.

City of Simulacra: This is a city built by and for the Simulacra, for the massive legions that would otherwise overwhelm existing cities.  They use their Hidden Ace Wishes to construct the permanent city with spells that become permanent, such as Wall of Stone, Galdur's Tower, and Mighty Fortress.  They also can replicate Mordenkainen's Magnificent Mansion for comforts when they're not magicking the city into existence or performing some task to earn money (such as scribing magic scrolls for sale).  The occupants of the City of Simulacra are also organized into Strike Teams.  Their Homunculi are all already in the Hall of Homunculi.

Hall of Homunculi:  This fortified, hidden location has around a Dozen Simulacra stationed in it, along with the vast majority of the Homunculi.  The Simulacra here have the job of calling the other Simulacra here from wherever they are when they're needed, with the Homunculi here effectively serving as one-way radios for them to get the notifications.  The Homunculi for the Simulacra stationed here are with the original caster and the Security Team, so they are constantly up to date on everything going on, and the original caster can issue orders to the Simulacra in the Hall of Homunculi through their Homunculi.  When potential danger is detected or suspected near the original caster and Security Team, the Simulacra stationed here will make the call on how many Strike Teams to call back, and when danger is imminent near the Security Team, the Strike Teams assembled hear will each take a pinch/piece of an "associated object" collected by the Recon Team and use a Hidden Ace Wish to Teleport to the original caster's location.

Example outcome:  an Aspect of Tiamat or the Tarasque shows up at a climactic event, and on turn 1, over a thousand wizards spontaneously appear all around her, and the foe is hit by over a thousand castings of Disintegrate from all sides that same turn.  Everyone else stands flabbergasted as something that was supposed to be a threat to the world was reduced to ash in 6 seconds by one man's Simulacra.  A man who has millions more waiting for their turn to be used.

5.5e Suggestion + Planar Binding + Magic Aura

Suggestion is pretty easy to get access to as it is only a 2nd level spell so you can have your whole party spam that to get through an enemy's legendary resistances, then Suggest they stand still and choose to fail the save against Planar Binding, enabling you to cast Magic Aura to make then the correct creature type then be enslaved by Planar Binding.