find them in your house, on the street, local art supply or craft store, thrift or hardware stores, online if you have to. etsy is good for vintage papers. use what you already have if you can, or go splurging on a few fancy supplies that light you up. whatever feels good to you.

not a tool, but something to prepare for: access to an inkjet printer.

a variety of papers to play and collage with, preferably not glossy - anything that inspires you, old book pages & covers, magazine pages, print-outs, vintage ephemera
tissue paper, used tea bags
back stapled wrapped canvases - 3 12x12 (or whatever size you like) and/or unprimed loose canvas (about 3ft)
glue - regular gel matte or matte mod podge
white gesso
acrylic paints in 5-6 colors that appeal to you (little bottles of craft paint for target are fine)
brushes (2-3 sizes. the cheap 1” ones you find at the hardware store are awesome)
ink (1-2 colors you like)
plain fabric scraps that you have around or can find at a thrift store (preferably cotton or silk, cheesecloth, lace)
embroidery floss in a couple of colors you like & needle
essential oil (i prefer wintergreen, but orange, eucalyptus, or lavender work too)
carbon paper (or transfer paper in black. i also highly recommend white and use red a lot)
soft pastels (2-5 colors you like)

various mark making tools you can find around your house or outside (an old toothbrush, sticks, feathers, sandpaper, incense sticks)
the plastic netting your vegetables or fruits come in
metallic foil
graphite pencils, charcoal sticks
white gel pen (uni-ball signo)
stabilo woodies