So what I'm attempting to do is create a Warforged Wizard that subclasses in Summoning minions and then buffing them to do the dirty work, but still be able to hold their own if needed, and I just figured it would be a safe bet to post here and see what would be the easiest way to go about doing so. I've never really played Wizard before, spent most of my time playing as a Warlock, and always gravitated towards magicking or bewitching other people to do things for me. So I figured why not just go all out and see how it is!

Thanks in advance for any advice or help I can get!

I highly recommend the School of Conjuration subclass. Copying conjuration spells will be faster and cheaper, you can conjure objects whenever you need to if you've seen it before like a key, chair, etc, your summoned minions get 30 temporary HP each and your concentration on a Conjuration spell cannot be broken by taking damage. You can also teleport 30 ft as an action or swap places with a minion (or any willing creature).

Recommended Conjuration Spells

1st Level

Find Familiar - a mini-minion that can scout for you and whose form can be changed to suit your needs and preference. Can also deliver Touch spells at distance for you.

Fog Cloud - Provides cover for escape. If you can later summon an Earth Elemental you could cover the battlefield with fog blinding the enemies while your elemental wails away at them unaffected - since it has Tremorsense. They're both concentration spells, but there are magic items that can get around that, I'll list something a bit further down.

Grease - Why not help your minion by casting grease underneath the enemy they're fighting? It can make that enemy prone so your minion has advantage to attacks against it. Also useful in slowing down enemies in pursuit. Also useful for making people trip down the stairs. Plus it can be funny to just watch people faceplant the floor.

Protection From Evil and Good - As a conjuror you may have to deal with all sorts of creatures from all sorts of places. Some of your own conjuring can carry risks as not everything you summon will be nice to you. This gives you some protection from such beings when you need it. Better safe than sorry. Bloody fiends.

Unseen Servant - Nothing screams Wizard more than conjuring servants to do your chores and carry your burdens (much better than Lydia!). Cooking, cleaning and carrying and more - they're incredibly useful.

2nd Level

Cloud of Daggers - Ok it's not "miniony" but this conjuration spell does small but reliable damage (no save against it) and can help you hold a choke point or wittle the enemy down quickly if your minions are able to corner or surround the target locking them into the area of effect.

Flock of Familiars - Like your normal familiar, but better. Scouting and touch spell delivery up to a mile away, no longer needing to use an action to see through them and seeing from multiple places at once? Oh yes.

Misty Step - Nothing says conjuration more than conjuration yourself to a new location. OK, it's only 30 ft. But it's a bonus action and being a conjuration spell means it will reset your Benign Transposition feature so that's 60 ft of teleporting in a turn. That can certainly come in handy. If you come to a locked door you can summon your familiar to the other side, on your next turn, use your action to see through the familiar's senses and then your bonus action to Misty Step. You've just gotten past a locked door - who needs rogues?

3rd Level

Galder's Tower - Why sleep in the rough or in tents or pay for rooms like the rest of your party? You're a Conjuror! So conjure this two-storey tower, complete with comfy furniture.

Sleet Storm - This spell covers a wide area and creates a lot of difficult terrain, even against flying enemies, that can cause people to fall on their arse. It is great to slow enemies down. It is also useful against enemy spellcasters as it makes it harder for them to maintain concentration on spells. It is also great for putting out fires if one of your Fire Elementals got a bit overzealous.

Thunder Step - When enemies slip past your minions and surround you, damage all of them and teleport away.

Tiny Servant - What deceitful blasphemy is this? A non-conjuration spell?! Ok, ok, hear me out. This is an 8 hour, no-concentration-required, minion that obeys you, has functional use because it's also an item, and it can even attack.

Summon Lesser Demons - This is a risky one but they're decent, you can keep yourself safe from them and they'll bring some chaos to your enemy. I mean that literally, they're Chaotic in alignment.

4th Level

Banishment - Another one?! Yeah, OK, it's not conjuration but if you want to be a master conjuror you need to know how to send things back, as well. The spell is Abjuration because it's focus is to protect you but it functions like conjuration. It banishes the target to a safe demiplane for the duration - if you're trying to protect somebody and an enemy appears you can banish the protectee, dispatch the enemy and bring that protectee back. If you use the spell on a creature from another plane of existence, like a fiend or demon, you can banish them back there and if you maintain concentration for the minute, they stay there permanently and will have to find a normal way back.

Conjure Minor Elementals - Small but feist they'll be useful in a fight, obey you, and if you conjure mephits they explode on death so multi-bomb-kamikaze to the enemy. Or if you have a Bard in your party - put on a show, they're adorable little dancers.

Dimension Door - AKA 'The Nope Button', in a bad situation? Nope out of it with this spell as you, and a buddy, can teleport to safety. Also useful for popping into town (literally) for shopping, bypass the stairs when feeling lazy, cross great chasms, and so on.

Galder's Speedy Courier - Got the McGuffin but too lazy to hike back to the Quest-Giver? Well, here you go. Split the party (are you nuts?) and need to pass something to the others, here's a quick and safe way. Staying in a hotel (dafuq happened to your tower?) and want to pay for an additional night but can't be arsed to get dressed and go downstairs? Use a spell. You're a wizard, after all, such inconveniences are beneath you.

Leomund's Secret Chest - It's pricey, but you're worth it. Great way to keep valuables safe. If you can't conjure a chest for your convenience, are you really a conjuror?

Mordenkainen's Faithful Hound - a minion that lasts 8 hours, guards a specific area, is invisible, can see invisible and ethereal things, can alert you and can attack intruders. Oh, and it can't be harmed at all. Pity the fool who tries to sneak up on you when you're sleeping.

Summon Greater Demon - Summoning demons is risky but there can be benefits. Even if you lose control you have ways to defend yourself, and they can bring much unpleasantness to your enemies. There's also another reason why you might want to consider this, but to be mysterious I'm going to wait until a little bit later to explain why.

5th Level

Conjure Elemental - Elementals are strategically great. You can conjure the right elemental for the area you aim to fight in. In exchange for that versaility and the powerful minion, there is a drawback that if you lose concentration it stays behind for the rest of the duration no longer controlled by you. However, that's not going to be an issue for long. You get 5th level spells on reaching 9th level but at 10th level you get a feature that means your concentration on conjuration spells cannot be broken. So, a powerful minion and no drawback. And it lasts an hour, too.

Infernal Calling - So this is a weird recommendation because on the surface, on its own, this doesn't seem worth it, does it? A 5th level spell for a devil that isn't controlled by you and you have to make Charisma checks to get it to do something... Yeah. Seems sucky. I mean, sure Devil's are powerful and often have powerful traits, but, what good are they if you're likely to fail to get it to do anything? It could attack you or your allies, it could just ignore you all and leave or even help the enemy. This is only useful if you have really high Charisma (and let's face it, that's unlikely) or you have that devil's talisman, which is even less likely. It could be useful to conjure a specific devil into a trap if you made it your enemy.. But otherwise, not great for the minions-R-us build. So why is it in the recommendation? You'll see. You'll all see! Muahaha--*ahem* - I mean, just wait a bit.

Teleportation Circle - Do I need to explain why the abiity to teleport across the world is going to be useful?

6th Level

Arcane Gate - Get the whole party across that chasm, or set one in front of you so when those distant archers fire at you, all their arrows come back at them, or use it as a way to get the minions/the party/is there a difference? to the enemy quickly. You can drop concentration when you want, even on other people's turns, so you can - initiative be willing - get your party there and then drop it before the enemy can use it.

Drawmij's Instant Summons - This is a great way to keep specific things safe until you need them. Cast it on things like your spellbook, magic staff, the mini-chest used for Secret Chest, and such. Can be combined with other spells for even more safety. It's a great backup. Also, great for leaving things at home, too big for your chest/bag, and if you ever do need them. Carpets of flying are great, but carrying it is a chore (you're better than that) and attracts attention if you're always using it, so bind it to a sapphire, leave it at home and if you come across a moment where you really need flight-- crush, poof, you have a flying carpet at the ready.

Scatter - Teleport people, minions, enemies, allies, whateveries all around in your favour, even yourself. Enemy Ambush! Oh no, they have us surrounded. *Cast* Oh yes, we now have you surrounded. Dead bandits.

Mordenkainen's Magnificent Mansion - Now, sure you have your tower and it's comfy, and it will do if you want something that sticks around, but your real living can be in this mansion with free food, drink, lots of servants, hot tub if you wanted it. Luxury. You could make your tower permanant, get a permanent teleport circle there, and put in other protections. On days you have the slot to use, make the mansion knowing you're incredibly secure.

Teleport & Plane Shift - As a conjuration master, you need to be able to get to where you want to go, even into other worlds.

8th Level

Demiplane - Your own little permanent demiplane to do what you want with. This will be incredibly secure storage, a great place to put those valuable things - if you ever need to summon the items consider using Instant Summons on them. You can make a trap plane and consider forging a tuning fork to it - if DM is willing - so you can Plane Shift enemies into it. You could have one like a Safe Room - how to escape an enemy that can teleport? Make demiplane, rush in, dispel the door and they cannot get to you. To use Gate or Demiplane spell they have to know that specific demiplane, and they don't, and to plane shift they'd need a tuning fork to it which there's no way for them to have. You could have healing potions and such stocked here, too. Unlike the mansion, it can't be dispelled. You're safe. I mean that might depend on how the DM runs demiplanes - because air might be an issue, but even for an average sized party you got a couple days, so that's enough to rest, recover and then you can plane shift/gate back out. Which reminds me, don't take this spell if you don't have plane shift or gate - because if the door closes after the hour or by being dispelled, you're kinda ****ed.

Mighty Fortress - While the tower and mansion should be more than enough, sometimes you're going to need a big place that isn't going to use up your spell slots every day. Enter the Mighty Fortress. It's a great substitute. It's costly, but it lasts 7 days. If you have the gold and time, you can make this permanent too. You can combine this with the towers to really make something special, if you wanted.

9th Level

Gate - Gate is useful in going to different worlds, especially if you have a lot of people to bring with you as it's a Portal that says open for a minute. However, the true benefit of this spell is that you can position and place the portal with precious and in whatevr way you like and you even decide the size, to an extent. Need a lot of water in a hurry? Gate to the Plane of Water and bring down a lot of it instantly. From your plane shifty shenanigans you might know of a nice big running flow of lava, so why not place a portal to it above your enemy's head? That'll burn. Gate has another function. If you name a creature on another plane it is summoned to you - and you get to decide the position and they don't even get a save. Hello enemy, meet my traps.

Wish - Yes. The spell that can rewrite all reality, is a Conjuration spell. And you're a fool if you don't take it. Seriously. While the big uses carry stresses (stat drops and 1/3 chance to never be able to cast it again), it does have a stress free "basic use": to replicate the effect of any 8th level spell (conceivably also any lower spell at 8th level) from any spell list. Here's the thing, you're replicating the effect but you're still casting wish. So, regardless of which spell you're replicating, it is Wish's casting time of 1 Action, Wish's casting level of 9th (for purposes of Counterspelling), and Wish's spell components of V (goodbye costly material components).  Make a backup body with Clone to safeguard from death, even old age, or make another you with Simulacrum to double your concentration, minion count and spell slots of 8th level and lower, and so much more.

--

Now, there's two more spells you may want to consider, but neither are conjuration despite fitting into the theme. These are the 3rd Level, Abjuration, spell Magic Circle and the 5th Level, Abjuration, spell Planar Binding. The idea is you summon the creature into a reverse Magic Circle and then cast Planar Binding. Durations and Casting times will be tricky and it's also costly. It is therefore recommended for higher levels where gold isn't a concern and higher level binding means you keep your minion for longer. This will be a lot easier if you use Wish or a Spell Gem of appropriate level. Spell Gems let you store a spell to cast as an action later. Wish also lets you cast an 8th Level Planar Binding as an action, no components required. You could alternatively Gate the creature into the reverse magic circle. You can also cast Glyph of Warding to store a Planar Binding and have it trigger on what you summon. Bound creatures are fully obedient. So, ask that Devil to give you its talisman, ask the Demon to provide its true name.

Many of your summon spells require concentration so why am I suggesting other concentration spells? Well, there's ways around concentration. A creature bound by Planar Binding sticks around for the Planar Binding's duration without need of concentration. Since higher bindings can be weeks to over a year, you could create an army. The Glyph of Warding can maintain concentration for the spell stored in it. There are items that can shift concentration to another by treating them as the caster - spell gems, for example, Ring of Spell Storing, and such. Put a beneficial spell into the item and give the item to the minion, or your familiar, or party member, and they can cast that spell for you and maintain concentration for you too. As mentioned, a Simulacrum is another you that acts as your minion, which can also cast and maintain concentration.

Finally, take a look at some of the Unearthed Arcana Conjuration Spells. They can really open up your conjuration options, if the DM allows them.

Something to consider with this idea is a lot of DMs and groups can get unhappy with summoners dragging combat to a crawl.  When that happens, expect an awful lot of AOE to clear that stuff off the board.  Make sure that everyone's OK with you doing this or you might be setting yourself up for a lack of fun when they get tired of it and "work around" it.