Trees and scratchers are a must, cats usually scratch furniture because there isn’t something else nearby to use. Trees give them a place to climb and feel safe up away from things. You should also have places for them to hide (boxes, piles of blankets, a bed in a quiet room, etc). As for toys, it really depends on the cat. Ours is super picky and only likes specific rattle balls from Amazon, small rattle mice, and some kickers (there are few others but they are all small and easy for her to cray around). But for every one toy we found she likes we have half a dozen she won’t touch. You’ll likely need to try a bunch to find what yours will enjoy.