Asklemmy

Bed bugs.

Positive outcome would be no more having to burn contaminted possessions (or wash them in very hot water many times).

Bedbugs, hands down.

I know you said that we shouldn’t say humans but I’m gonna say it anyway:

Humans.

Sorry.

Landlords

Ticks.

They seem to just make everything worse, and I don't think anything only eats ticks. Not to mention the diseases they carry.

I hate to say it, but getting rid of mosquitos would probably have bigger consequences than that. The females are the only ones sucking blood, the males on the other hand help pollinate plants, exterminating them could potentially affect our food production lines...

... But not gonna lie I'd still genocide the fuckers, ecological damage be damned.

Canadian Geese, the animal that Canada stored all its rage inside and sent to battle the United States

Bedbugs. That's a terrible thing to happen to anyone.

Most positive effects on the planet but not humans?
Cattle, they're a major source of greenhouse gasses, as are all the industries built around growing, processing, and transporting them.

Pandas. I mean, they really don't seem like they want to exist in the first place. And China get's to finally shut up about them.

I'm off the opinion that no animal would be beneficial to remove. In almost every instance where we have exterminated a species there has been negative unanticipated consequences. Even mosquitos and bed bugs, there are predators that eat them and subsequent predators that eat them and so on. It's kind of like the butterfly effect. It's a balance formed from eons of coexistence that is not to be tampered with. There is so many examples where scientists try to introduce an animal to exterminate another that has gone horribly wrong. Regardless of my opinion, all living things have a part in our world. I'm not a vegetarian btw, but I do use Arch.

Mosquitoes

Deleting all mosquitoes would have a significant impact on the environment, many birds and spiders mainly prey on them. Delete just mosquitoes that bite humans. It's a much narrower range and wouldn't affect the environment as much.

Mosquitoes are pollinators. Sucking blood and being annoying is only a small part of their functionality.

Cockroaches... as far as I'm aware, they don't contribute anything to the eco system, they're just pests.

Unfortunatelly, not even a nuclear war can erradicate them 😒.

If you gave any random person god like powers to do whatever they wanted, they would immediately eradicate mosquitoes as their first act.

I think I'm going to go with Africanized honeybees. My understanding is they're a man-made calamity, so pressing the delete key on them wouldn't like, upset the circle of life and piss off Mufasa or whatever.

Ticks and botflies. We don't need maggots making a home in our skin. Even worse is what they do to animals like sheep.

Mosquitos are mainly an annoyance to me and I can deal with them.

Hard to say. Mosquitos, is probably not one of them because even as much as we hate them, many animals prey on them, so unless other insect replaces them as a food source for those animals, them disappearing would probably affect many other species and subsequently, other species that may feed or depend in some form on those that feed on mosquitos.

My answer would probably be ticks, since I don't think there's many animals that feed on them and their only usefulness is population control, which should be doable by other species either way.

Edit: bed bugs as well, since it was mentioned by other commenters, I hate those fuckers and last I checked they weren't any animal's primary food source.

Chiggers. Fucking hate those things.