I really like how you guys have been taking inspiration from nature for some of your virus strains. The stuff you can find there is loads weirder than anything you could come up on your own. A pretty pink mushroom covered in drops of what looks like blood? How odd!
Anyway, here's some weird things I happen to have chanced upon on my own that might give you inspiration for some new strains.
Hagfish
This is a type of jawless fish that is really gross and creepy. It's an ancient type of fish with no skeleton, only cartilage. Their mouths are really creepy when open.

And even kind of creepy when not.
They sometimes hunt, but mostly eat dead things, and are known for burrowing into their food to eat it from the inside out.
They are also very, very slimy, which serves at a defense against predators.
Dodder/Witch's Hair
This is a parasitic plant that cannot photosynthesize due to lack of chlorophyll, hence the yellowish color. It grows around photosynthesizing plants and eventually kills them.
More pics: 1234
Hatchlings
Let's face it. Baby birds can be pretty damn weird looking.

As much as I'd like to suggest for new viruses, part of the excitement is the surprise of what your strain is going to be. I once made a thread similar to this one but was told by staff that they like to work on their own with the zombie strains, and that they had a lot of ideas already :)
Frankly, I'd prefer more actual diseases/parasitic takeovers and less mutant, humanoid animals. D: I feel that the mutant animals are better suited to be Zapper skins. They stick out compared to the old zombie skins.
Honestly, I don't want more sea animals skins, or plant/fungi skins
They had their year, it's cool. Moving on to something else, please
Probably unpopular opinion but honestly I'd like for there to be 1 "cute" zombie every year, like Love Bug, Pinkie Patch, Freckle Fever, Bubble Jelly etc. The rest can be extremely grotesque if they want but I would be a very happy camper for 1 cute one every year.
Count me with the people who would like 1 cute, heart covered virus a year. I also agree with more actual disease type viruses. Maybe something that looks like a graveyard pet, or a nightmare one.
As cool as the animal ones are, I'd much rather see more...natural looking viruses. Maybe we could get an actual cordyceps strain some year :D
As much as I love the alien/animal/plant inspired strains, I do miss the older ones. I miss the more traditional zombies, and I missed the hearts/cutesy one this year (although I still loved them all !). The first year all of them had hearts somehow, except for Boobitis which had its heart literally ripped out, and I'd love to maybe see something like that again.
I'd really like to see something opposite Love Bug, which is happy and full of love. Something blue/grey that based on heartbreak instead of love c:
I really wish we'd return to virus strains that actually fit the HA base. It looks like Bright Bite and Blood Rush don't have a single line from the actual base remaining. I'm very sick of strains going big super early and just getting kind of ridiculous. I want viruses we can actually wear and work with! I don't mind a bit outside the lines but its gotten out of hand.
I also miss the actual disease zombie viruses. Fungi and animals are neat but idk, I'd rather have more traditional zombie skins. We've got plenty of weird, random ones. With how much the artists have improved over the years it would be nice to have a "throwback" year with more typical zombie skins that fit the HA bases, like the first year.
A return of HA base sized infections is an excellent idea! (And for too simple for me to ever think of. :P)

I'm definitely also on the side of having one cute skin per year, as those tend to be my favorites. :P
Also, I agree with some of the newer viruses being too hard to work with. For example, I like Bubble Jelly, but I have no idea how to make a workable HA out of it. Too many things sticking out of it makes putting on clothes nearly impossible.
While I'm in favour of letting staff design the skins as a surprise, I would like to throw my support behind skins that fit the base and you can actually wear clothing over. I liked the idea of the plant-based skins this year, but I didn't bother getting either of them because there's no way to work with them, and that was disappointing.
Exactly what I was going to say. When the viruses get too blobby and too detailed, they're nearly impossible to work with. Faceworm, Baker's Kiss, and Gross Fungus do this, too.
I don't mind some details going outside the lines, because it keeps things interesting. Doom Bloom, Angler, Carchari, and Deathslug all spill over, but they're still easy enough to work with.
Other than that, I'd rather be surprised by next year's strains, so I won't give any specific suggestions. :D

Covering your base with clothes?

You're a zombie. Run natural. Don't wear these horrible, gaudy clothes. Showcase your skin, love every single of your blisters
btw, best zombie year was 2012.
I love the idea of having at least one "cutesy" style virus. My favorites are the classic viruses from the beginning.
</p>(You may have been being sarcastic, I honestly can't tell.)