Name: Gravesoil Sediment Golem
Rank: 4
Attribute: Earth
Monster Type: Rock/Xyz/Effect
Effect:
2 Level 4 monsters
If this monster has a Earth Attribute monster as a Xyz material it gains the following effect
Once per turn you can detach one Xyz material from this card then change this card to Attack position to special summon one Level 4 Earth attribute monster from your graveyard.
ATK/DEF: 0 / 2800

and because I like this card, have a description of appearance.

A hulking mass of crumbling dirt and bones from a nearby crypt, it moves with unseen force. It is the unmovable unstoppable carrier of the earth. Fear what happens if the dirt crumbles away to reveal what the grave that had become truely mobile contained.

Whew, that's a little much. Scale it down a little, though I'll let you choose what to scale down.

<Snipped quote by Ammokkx>

The hand destruction was a bit much, looking at it again. How's this instead?

Deepspace Sniper
Level 4
Light/Machine/Effect
1200/600
When this card destroys a monster by battle, you can target one Set card on the field: Destroy that target. If the destroyed card is a Spell/Trap card, your opponent loses 500 Life Points.

<Snipped quote by Tojin>

I still say you should lose the 500 LP part.

<Snipped quote by Scarifar>

Deepspace Sniper
Level 4
Light/Machine/Effect
1200/600
When this card destroys a monster by battle, you can target one card in your opponent's hand: Destroy it, then if it was a monster, your opponent loses 500 LP.

Name: Assistant Tactician
Level: 2
Attribute: Earth
Type: Warrior
Monster Types: Tuner/Effect

Effect: If this card is in your Graveyard You may Special Summon it: if you do, you may also Special Summon 1 level 4 or lower Warrior-Type monster from your Hand or Graveyard. Neither monster Special Summoned by this effect can attack this turn. Banish this card when it leaves the field if summoned this way.

Attack: 0 Defense: 1000

As usual I have no idea what to set for ATK and DEF values so I put random stuff. Also not sure if the bonus summon should be only hand. Thought? ^.^

Name: Retsugrata, The Trap Buster Dragon
Level/rank: LV 7
Attribute: DARK
Monster Type(s): Dragon
Effect: Twin-Headed Behemoth + Mirage Dragon
This card cannot be Special Summoned, except by Fusion Summon using the listed Fusion Material monsters. While this card is face-up on the field, negate the activation and effects of Trap Cards and destroy them. Then, reduce this card's ATK by 500 for each Trap Card negated this way. During the End Phase, you can discard one Trap Card from your hand to change this card's ATK to its original, printed ATK.
ATK/DEF: 2600/2000