i use small cymbals on most of the drums - i sometimes use a mid tom and if i stack two splashes on it, i get a nice short hi hat sound. drum contact gets a kind of cool ultra short dead tom sound as well.
putting small cymbals upside down can have cool results as well, i’ll set them up to interfere with each other, or put larger cymbals on my floor tom. lots of sound manipulation possibilities there, you can steady the cymbal with your hand in the middle and bow it to get both drumhead and cymbal sound, i’ve gotten wild pitch bends by smacking just outside the bell with a mallet while applying pressure with the bell.
i have all sorts of shakers and bells i like putting on drums - dried goat claws, dried nut/seed shakers, indian dancing bells. i’ve gotten good results putting little drums on my snare, i have a little tamborim that works especially well. kalimbas can actually resonate through the drum which is super cool.
there’s also just so much to be said for using technique and sticks for different sounds, i have these worn out plastic rutes that are great for brush sounds when i want to use something closer to stock technique. traditional brushes are extremely underrated i think. i’ll use dead strokes to get muted sounds without muting a drum, or choke up or back on the stick and strike different spots on a drum for different sounds.
i like stacking cymbals on cymbals, right side up and upside down. i never use top felts or wing nuts so it’s easy to do this stuff in the moment and keep things modular. i grew to love the sound of cheap beginner model cymbals, when you tape them down you get some interesting sounds, and when they break - which they will - they only sound cooler.