Hi, thank you so much!
The software for making voxels I used is MagicaVoxel, it's really fun to work with and has some really nice (imo) lighting presets if you wanna render stuff in it, highly recommend you check it out if you ever feel like dipping your toes into voxel art:)
The grainy filter was just unity post-processing on the main camera, I would love to learn to use render textures instead, but this turned out to be a nice substitute (and again, very easy to use, which is a huge plus:D).
I was thinking of highlighting the pick-up-able objects as the player hovers over them, but again, didn't have time, will have to look into that as well later:)
I will neither confirm nor deny my stance on Rubber Band