Tribute Monsters - 2
1x Mobius The Frost Monarch
1x Gravekeeper Chief

Non-Tribute Monsters - 16
3x Gravekeeper's Spy
3x Gravekeeper's Spear Solider
3x Gravekeeper's Assiliant
2x Night Assiliant
2x Mystic Tomato
1x Breaker The Magical Warrior
1x Exiled Force
1x Tuksuyomi

Spell Cards- 15
3x Necrovalley
2x Fissure
1x Brain Control
1x Snatch Steal
1x Heavy Storm
1x Mystical Space Typhoon
1x Nobleman of Crossout
1x Dark Hole
1x Lighting Vortex
1x Premature Burial
1x Book of Moon
1x Swords of Revealing Light

Traps- 7
3x Rite of Spirit
1x Torrential Tribute
1x Call of the Haunted
1x Waboku
1x Dust Tornado

Please rate/ Fix my Deck and I will do the same for you.
Thanx

First off, welcome to tha Realms....So you want to get your deck ready for Regionals. I can lend some constructive deck opinion so that you and your deck gets that Qualifier......ready?

Tribute Monsters - 2
1x Mobius The Frost Monarch
1x Gravekeeper Chief

Non-Tribute Monsters - 16
3x Gravekeeper's Spy
3x Gravekeeper's Spear Solider
3x Gravekeeper's Assailant
2x Night Assailant
2x Mystic Tomato
1x Breaker The Magical Warrior
1x Exiled Force
1x Tuksuyomi

Well, there are a few mistakes here but you shouldn't worry too much. 1st, Night Assailant is restricted to 1 so that's 1 spot open. You really don't need Exiled Force for this deck since Gravekeeper's Assailant & Tsukuyomi can handle pretty much every monster in the current meta. Also, you may want to include some Flip Variety in your deck in case the Nobleman of Crossout gets lucky so try out these:

DROP
1 x Night Assailant
1 x Exiled Force
1 x Gravekeeper's Spy

ADD
1 x Sangan
1 x Mystic Tomato
1 x Gravekeeper's Guard

Spell Cards- 15
3x Necrovalley
2x Fissure
1x Brain Control
1x Snatch Steal
1x Heavy Storm
1x Mystical Space Typhoon
1x Nobleman of Crossout
1x Dark Hole
1x Lighting Vortex
1x Premature Burial
1x Book of Moon
1x Swords of Revealing Light

I can understand that Smashing Ground is an extremely hard common to find which is why you have the 2 Fissure in there so those can stay. Sure, the main card for this deck is Necrovalley but you don't want to wait in drawing it so add 1 Terraforming. Also, since the monsters can clear the field w/ Necrovalley as fast as a Normal Spell, Vortex won't be necessary. And since Necrovalley is there, Premature won't see too much use...Gravekeepers are naturally aggressive and your opponent's biggest distraction will be Necrovalley so how do you plan on getting their attention away from Necrovalley?

DROP
1 x Lightning Vortex
1 x Premature Burial

ADD
1 x Terraforming
1 x Wave-Motion Cannon

Traps- 7
3x Rite of Spirit
1x Torrential Tribute
1x Call of the Haunted
1x Waboku
1x Dust Tornado

Your Traps are not only going to be the most tricked out part of your deck, it's also the backbone. Waboku is better being in the Side Deck and with Heavy Storm, MST, Breaker, and Mobius in there already, D-Tornado won't be too helpful. Also, expect to see a lot of Mobius' at the Regional so try out either Solemn Judgment or Divine Wrath. The Keepers are all about speed & recovery and Rite of Spirit takes care of the recovery while Magician's Circle gives you uncanny speed. The Keepers are all Spellcasters, right?

DROP
1 x Dust Tornado
1 x Waboku
1 x Rite of Spirit

ADD
2 x Magician's Circle
1 x Solemn Judgment / Divine Wrath (try out either one of these)

So with that pointed out, the finished model looks like....

Tribute Monsters - 2
1x Mobius The Frost Monarch
1x Gravekeeper Chief

Non-Tribute Monsters - 16
2x Gravekeeper's Spy
3x Gravekeeper's Spear Solider
3x Gravekeeper's Assiliant
1x Gravekeeper's Guard
1x Night Assiliant
3x Mystic Tomato
1x Breaker The Magical Warrior
1x Sangan
1x Tuksuyomi

Spell Cards- 15
3x Necrovalley
1x Terraforming
2x Fissure
1x Brain Control
1x Snatch Steal
1x Heavy Storm
1x Wave-Motion Cannon
1x Mystical Space Typhoon
1x Nobleman of Crossout
1x Dark Hole
1x Book of Moon
1x Swords of Revealing Light

Traps- 7
2x Rite of Spirit
2x Magician's Circle
1x Torrential Tribute
1x Solemn Judgment / Divine Wrath
1x Call of the Haunted

Lastly, for addtitonal help, I can suggest some excellent Side Deck cards for this deck...

Royal Tribute - Most opponents like to hold their resource monsters in their hand and wait for the right time to summon. With Necrovalley, both players discard all Monster cards in their hand and with Rite of Spirit, you shouldn't have a problem. Also, Royal Tribute can combo well with this next card....

Broww, Huntsman of Dark World - Combo this w/ Royal Tribute and its effect lets you draw a card for each one that gets knocked out of your hand but if your opponent knocks it out, you draw 2 cards instead of 1.

Mirage Dragon/Pitch-Black Warwolf - If you notice, most traps used in the meta are Battle Phase traps (Sakuretsu Armor, Widespread Ruin, etc.) This Dragon/Beast-Warrior stops your opponent from using Traps during either Battle Phase. Both carry a decent 1600 ATK.

There are other good choices...all you have to do is look for them. I hope this helps and if you manage to make the changes in time, tell me how the Regional went....