Why do you need a closet?

Apple pie - that is where the water heater is

"... I have a stacked washer dryer. They are both frontloaders."

Dryers are always frontloading ... except Fisher & Paykel offered a toploading dryer from approx 2004 to 2010.

"Don't get the kind of washer/dryer where the bottom unit (usually the
washer) has a 45 degree angle cut into it because the washer is a top
loader."

That is known as a *stacked* set, which can be operated only in the combined configuration. Maytag and Speed Queen (maybe others) had such units with a frontload washer. Speed Queen still does. https://speedqueen.com/products/home-products/stacked-washers-dryers/  LG also recently introduced one, called the WashTower. https://www.lg.com/us/washer-dryer-combos/lg-wkgx201hba-washtower

Regular frontloader sets, with the controls on front instead of a backsplash panel, are known as *stackable* being that they can operate either stacked or separately side-by-side.

We have a similar utility closet. My husband made a bookshelf on wheels which slides into the space in front of the furnace. It is nothing fancy, but he sized the height of shelves exactly to hold various spray bottles & bins of lightbulbs, microfiber towels, etc. It rolls into the hallway when the repairman comes or the filter needs replacing. We put a set of flat wall hung wire shelves above that on the side wall for little cleaning things like Brasso. And we hung hooks from the ceiling for tall things like dustmop. Short folding step ladder slides in under those. Biggest regret that we didn't add an electric outlet for charging stuff.

I have elsewhere a laundry closet w/stacked machines and deep shelves beside them sized for laundry baskets and clothes maintenance stuff like detergent & spray wash, mending, iron, etc etc. I have no place for lay-flat-to-dry...partly because I just don't buy such things, but I have seen slide out wire contraptions. that fit under a shelf. You have enough room for a small ironing board that hangs on the door & folds down...I've had one in the past & it was more than adequate for the little bit of ironing we do. Left-handed ironing might be an issue if you iron a lot.

I lust for your laundry sink, which could have a big dog food bin beside & cabinetry above. And that long wall which I would fill with hooks. Don't forget a trash can.

Thank you!! Are you happy with your stacked washer and dryer?

My daughter bought the Washtower 2 months ago and really likes it.

She has shelves to the right and a rod over that in order to hang clothes. She can store laundry baskets on the shelves under the hanging rod.

The nice thing about the washtower is that the controls are in the middle and easier to read than when they are on top of separately stacked washing machines.