I would listing down from bad to worse Imps. And I know I've said this before but I hate those little critters. They're more annoying than Zombie Chickens and Ballooon Boy or Mangle. The one thing that makes them more annoying is their constant laughing....Ugghhhh

Imp Mummy

This Imp was added to the 1.7 Update along with Mummified Gargantuar. I still hate Imps but this on is more tolerable. It's not much of a threat. Hate Rate: 5/10

Yeti Imp

I'm getting coins from this guy....just kidding. I never played Garden Warfare (though I wanted too). This is the PvZ2 version. It's not much of a threat. Sure, it can show up during Snowstorm Ambush but they get owned eaily. Hate Rate: 5/10

Dodo Rider Zombie

It is technically an Imp. And lo behold, the only Imp that never do that annoying laugh. Plus, him and his dodo are easily beated by Hurrikale or Blover. In fact, it is my favourite Zombie :3 Hate Rate: 4/10

Bug Bot Imp

They have a slightly higher health but they are not much of a threat. They can be blown away by Blovers at a right time when the Bot Swarm Ambush happens, they can be disabled by E.M. Peach and can killed with one hit from Magnifying Grass. Hate Rate: 6/10

Imp Monk Zombie

I'm pretty sure they are the reasons the gravestones in DA kept spawning. I mean, come one, they are the only zombie to utilize the Necromancy ambush in Arthur's Challenge. But not much of a threat either so... Hate Rate: 6/10

Zombie Bull Rider

He is one of the freakin' main reasons I lost lawnmowers and losing Big Bad Butte several times. He's is basically the right definition of annoyance. I feel nuetral for his bull though. Hate Rate: 8/10

Imp Pirate Zombie

When they are either launced by the Imp Cannons or come out of the barrel, they get very annoying. They are the main reasons I kept losing Dead Man's Booty. Hate Rate: 8/10

Imp Dragons

Freakin'. Imp. Dragons. They are the high level of annoyance. Why? Most of you already know: immunity to fire. And they show up with the rest of the zombies in Arthur's Challenge whenever I start a level. Basically a zombie-spawn magnet. And their immunity makes Cherry Bomb, Jalapeno and other fire-based plants not being able to take it down. Hate Rate: 9/10

Imp Mermaid Zombie

Surprise Surprise. Top of the list. Like Miles said, this Imp's freakin ambush Low Tides is OP. They always try to ruin my perfect strategy. They are also one of the main reason BWB - Day 16 is hard. They are basically trolling with their high level of annoyance. They are more freakin' annoying than the other Imps. They are basically the mastermind of level hardness. Hate Rate: 20/10

So there you have it. Feel free to comment.