Switch to eco paints free from volatile organic compounds (VOCs) most brands now sell low VOC paint
Use water based gloss or eggshell rather than oil-based although some companies now use vegetable oils
Use plant based wax and varnish
Look for chalk based paints for furniture
Donate any leftover paint before it dries up!
We haven't used wallpaper in our house but there are non-toxic water-based inks and paper that is FSC (Forest Stewardship Council) certified