Here are my custom cards. They're meant to be legacy support for the Gradius monsters, hence all the "LIGHT Machine-type monsters you control with 1200 or less ATK", rather than just "Deepspace". (I hope this is the right place to post them...)

Deepspace Scout
Level 4
Light
Machine/Effect
When this card destroys a monster by battle, you can target one card your opponent controls: Destroy that target. When this card is Summoned, you can Special Summon one LIGHT Machine-type monster with 1200 or less ATK from your hand or Graveyard, except “Deepspace Scout”.
1200/800

Deepspace Stunner
Level 4
Light
Machine/Effect
Once per turn, you can target 1 monster your opponent controls: change its battle position, also negate its effects until the End Phase. When this card destroys a monster by battle, during the rest of this turn, your opponent cannot activate cards or effects.
1200/900

Deepspace Berserker
Level 4
Light
Machine/Effect
This card gains 300 ATK for each LIGHT Machine-type monster with 1200 or less ATK you control during damage calculation only. When this card destroys a monster by battle, you can add one LIGHT Machine-type monster with 1200 or less ATK from your Deck to your hand.
1200/0

Deepspace Infiltrator
Level 4
Light
Machine/Effect
When this card destroys a monster by battle, your opponent loses 600 Life Points. This card cannot be selected as an attack target.
1200/100

Deepspace Suffocator
Level 4
Light
Machine/Effect
When this card destroys a monster by battle, you can reduce the ATK of a monster your opponent controls by 200 times the number of LIGHT Machine-type monsters with 1200 or less ATK you control. During each of your Standby Phases, all monsters your opponent controls lose 300 ATK. When a monster reaches 0 ATK while this card is face-up on the field, it is sent to the Graveyard.
1200/1000

Deepspace Beacon
Normal Spell
Add one LIGHT Machine-type monster with 1200 or less ATK from your Deck to your hand. If your opponent controls at least 2 more monsters than you, you may Special Summon one LIGHT Machine-type monster with 1200 or less ATK from your Deck instead.

The Depths of Space
Field Spell
Once per turn, you may target one LIGHT Machine-type monster with 1200 or less ATK you control: when it destroys a monster by battle this turn, if its effect activates and resolves, you may resolve that monster's effect twice. (This does not require that monster to destroy a monster in battle again that turn.) All face-up LIGHT Machine-type monsters with 1200 or less ATK you control gain 400 ATK and DEF during damage calculation only.