I'm using Ren'py for the game itself, and for the sprites I'm using procreate. For music I'm using free midis and converting them to .opus files with openMPT and a nice soundfont via sforzando. The backgrounds are all creative commons photos I've resized, posterized, and edited using painttoolSAI2 and an online posterize filter. the sound effects will likely be from freesound and potentially some of the halleylabs free resource packs (if you're making horror or something involving VHS tapes i highly recommend checking out the halleylabs resource center!!)
I might also use OpenClipart for some graphics (like fake logos in backgrounds, or bootleg anime posters lol)