My recommendation is a small thing: a trashcan with a swinging lid!
Covers the trash, reduces smells, will prevent trash tetris (sometimes), and very good instead of foot-pedal opening trash cans or trash cans put in a cupboard.
Another thing are toothbrush holders that stick to mirrors. Might jog that memory of needing to brush your teeth!
Wall-mounted keyholder by your door, too. Anything I put on a flat surface will eventually be lost or covered with more junk & papers. My keys are WALL-ONLY!!!
What item(s) have helped you with your struggles?
Me: Hyperactive, lacks object permanence, forgetful.
My partner: Inattentive, anxious, distractable.
For us it’s mostly been smart home stuff. Our doors have keypads, and they lock automatically if we forget to lock them. Smart speakers take notes and set reminders the moment I want to take a note. I used to have a “Magic Mirror“ that showed my calendar. From plants to lizards, we got lights on timers.
The other part is just planning.
We organize things by location and use, and work with each other. If she’s on a task, I have to let her think it out, or else she forgets stuff. If I’ve left something out and she doesn’t know if I’m done with it, she won’t put it away - lest I forget I was even working on something. We have a few free spaces in the house where we can ‘dump’ stuff - confined areas that visible though they don’t get lost/must be tended sometimes, so we can ADHD, without making out of control messes. We are intentional about where things live - if something gets put up and one of us can’t find it, we wind up with multiples of that item.