Maybe this combo would work well...

Rivalry of the War Lords + Ojama Trio

Since the opponent can't summon more than one type of monster they cannot get their monarchs out on the field. The ojama tokens can't be used for a tribute summon so they could be hard to get rid of and since there are three of them it would make it even harder for your opponent.

Hehe, too combo-centric, but that is one funny combo :) I'd play it for sure :)

lol... and if you added someone who could attack your opponent's life points directly too instead of hitting the tokens, then it could become even better, except for the fact that it probably would be hard to get all three

Final Attack Orders
Curse of Fiend
Windstorm of Etaqua
Zero Gravity
Gravekeeper's assailant
Monsters with Piercing damage.

Any of these will get the job done just fine.

Add a few copies of Fox Fire and Creature swap, maybe a D.D. Guide and a lot of monster removal to ensure they won't be using any of their own monsters.

Something like

3x Ojama Trio
3x Rivalry of Warlords
2x Final Attack Orders

2x Creature Swap
2x Mystic Box

3x Fox Fire
3x Cyber Dragon
2x The Fiend Megacyber
3x Great Maju Garzett

Fox Fire swap or Ojama Trio puts a non-tributable monster on their field, which will lock the field with Rivalry. Cyber Dragon and the Fiend Megacyber often meet their special summoning conditions with this deck, And Great maju Garzett can't just tribute off one of these guys, it can easily trade off whatever you get from swap to create a behemoth.

.

[jank]
eh This could also work/

Rivalry x3
Ojama x3

Kaiser Colloseum x3

Monsters x some

So basically, you either pop an Ojama and Rivalry, or you pop an Ojama, set a monster, and play Kaiser.
[/jank]

Your jankiness is rubbing off on me :p And Colloseum also works with the fox fire swap.

if Ameba switches contorl to your opponent they lose 2000 LPS...........

And how is that going to stop monarchs ? They'll just tribute it away for monarch and hit you over the head.

....well if the other player had less than 2000 LPS.........................

There are better ways to deal 2000 damage than through a combo.

What about this:

2x black pendant

Two other cards that might work are Hard Selling Goblin and Grave Protector against Treeborn's effect.

To block out Treeborn Frog, I suggest The Transmigration Prophecy or D.D. Crow, neither of which have actually been mentioned yet. I suggest both of those not only because they can take the Frog out of commission, but also because they do more than that. They both also stop Premature Burial, Call of the Haunted, Destiny Hero Disk Commander, Destiny Hero Fear Monger, Destiny Hero Dasher, Destiny Hero Malicious, Overload Fusion, Miracle Fusion, Dragon's Mirror, The Creator, Sacred Phoenix of Nepthys, Vampire Lord, et cetera. A slightly more erratic card to block Treeborn Frog would be Xing Zhen Hu to keep useless Spells or Traps on the opponent's field. Of course, just waiting for them to play a face down card and then activating Royal Decree would probably do it a lot better. Dark Ruler Ha Des can do the job very well, I have noticed many people around here have started using it.

i side Xing Zhen Hu it's my answer to burn it works really well and it's funny

Opps i meant Hard Selling Zombie cause it would send Treeborn to the bottom of the opponent's deck.