Number Ci107: Galaxy-Eyes Prime Tachyon Dragon (Limited)
https://imgur.com/8l0Z7g2
During either player's turn, Once per turn, if this card would leave the field; instead Detach one Xyz Material from this card; until the End Phase, this card cannot leave the field.
You can detach all Xyz Materials from this card, all your opponent's face-up cards' effects are negated. This card must have an Xyz Material to resolve it's effects. Once per turn, during your Battle Phase, if a Spell/Trap is activated, you can negate the activation of that card, and destroy this card. During the 2nd Standby Phase that this effect is activated, Special Summon this card.
Hypernova (Limited)
https://imgur.com/cRufPK9
Destroy all cards on the field. Add 1 "Hypergiant Star" Spell Card from your Deck to your hand.
Hypergiant Star (Semi-Limited)
https://imgur.com/aDtSePu
At the end of each turn, both players discard 2 cards or take 1000 damage.
Supermassive Black Hole (Limited)
https://imgur.com/bGF7ilc
Destroy all cards on the field. This card's activation cannot be negated.
Galactic Quasar (Limited)
https://imgur.com/XVekVK9
Destroy all Spell/Trap cards on the field. This card's activation cannot be negated.
Divine Shield of Darkness (Unlimited )
https://imgur.com/xruBGob
When your opponent's card is activated and you control a DARK attribute monster, negate the activation of that card and destroy it, then your opponent takes 1500 damage. You can only use this card once per turn.

my opinion 

Number Ci107: Galaxy-Eyes Prime Tachyon Dragon: unlimited (summoning conditions ? This card's effects are ok but the art is bad)

Hypernova: banned (too op)

Hypergiant Star: limited (can be abused in dark world, shaddoll and others)

Supermassive Black Hole: banned (ridiculous)

Galactic Quasar: banned (the effect is the same as heavy storm, and heavy storm is banned)

Divine shield of Darkness banned (solemn judgement for any dark attribute deck ? Nonsense)

Yep all of them are too powerful as Sebek said.  When making a card you have to pick reasonable effects.  Me and a few others only get away with broken effects because we slip in an equally broken downside to counteract them.

Here's some examples of more reasonable versions.

Hypernova:
Normal Spell
This card can only be activated if you have Hypergiant Star on your side of the field.  Destroy All Hypergiant Star cards on the field and all Monsters as well.  Any Monster destroyed by this effect has its effect negated. You can also discard one card from you hand to add one Hypergiant Star if the previous effect successfully resolves.

Hypergiant Star:
Field Spell
During each player's end phase inflict 1000 damage to the player it is the turn of.  A player can discard 1 card from their hand to gain life points instead of taking damage.

Supermassive Black Hole
This card can only be activated if you have Hypergiant Star on your side of the field and you have 3 or more cards in your hand.  Destroy all cards on the field and all cards in your hand, this card's effects can be negated by your opponent by them discarding 3 cards from the top of their deck.

Galactic Quasar
Normal Spell
This card can only be activated if you have Hypergiant Star on your side of the field and if you have 5 or more cards left in your deck.  Destroy the top 5 cards on you deck and all spell and trap cards on the field.

The last one I got no clue on, but the others I tried to keep them semi-true to their original effects while givning them reasonable costs and conditions to tie them down a bit.

Sorry for op, just see alot of either underpowered cards or overpowered but extremely limited in use.
So how about more reasonable versions. @Stormwing I like your versions except for black hole and quasar.
I understand it's to make it less op, but I would like to edit it.
Supermassive Black Hole (Limited to 1)
This card can only activated if you have played Hypernova and have Hypergiant Star in your
graveyard. (the rest is the same as yours)
Galactic Quasar
This card can only be activated if Supermassive Black Hole is in your graveyard (the rest is the same)
Hypergiant Star is semi-limited, Divine Shield of Darkness is limited to 1 and here's its new effect:
When an opponent's Spell/Trap is activated that destroys or banishes a card on the field, and you control a DARK attribute monster, Pay 500 lifepoints, negate the activation of that card, and destroy it. This card can only be activated once per turn.
Ok i'll get new pictures. If you're wondering if I made those pictures, I didn't.