More cards

[HomoSapientissimus]

Xyz Gate
Trap/Normal
Target 2 Xyz Monsters on the field; return those targets to the Extra Deck, then Special Summon 1 Xyz Monster from your Extra Deck whose Rank is equal to or lower than the total combined Rank of those targets, and if you do, you can attach up to 3 monsters from your hand or Deck to that monster as Xyz Materials, then draw 1 card. (This Special Summon is treated as an Xyz Summon.)

Over-Hundred Chaos Universe!!
Trap/Normal
If you take Battle Damage: Xyz Summon 1 "Number C10X" monster from your Extra Deck, where X is a number between 1 and 7, using monsters from your Deck or Graveyard as Xyz Materials. The monster Special Summoned by this effect cannot activate its effects until the end of your next turn.

Dimension Buster
Trap/Continuous
Monsters destroyed by battle or card effects cannot activate their effects that would activate in the Graveyard.

[Slinky]

Stop posting please.

[Tinkerer]

You haven't quite got to the balanced standard YCM expects, but you're getting there.

XYZ gate is still much too powerful. The fact that it replaces itself and gives you a completely usable XYZ at the cost of two XYZs (including opponent's ones, might I add) is too much. Maybe if you limited it to returning your monsters, did not give the materials and didn't count it as an XYZ summon, it would be more balanced.

Over-100 is also way too strong. Firstly, you never specified how many materials could be put on the monster. Secondly, the condition is way too easy to fulfill. Again, not giving it materials is the best way of limiting it, but I'd also recommend adding a "when the monster leaves the field, banish it".

Dimension Buster is the fairest of the three (maybe you should stick to 1-2 sentence cards?). However, even with the limitation that the monster basically has to be sent from the field for this effect to work, it'd still likely go the way of soul drain and d-fissure and limited to 1.