Omg that actually is so amazing to hear!!
I have a few recommendations; Slow feeders to put the canned kitty food in! but get worn out after awhile and need to be tossed/sold lowering the selling price for them but still get some coins. Scratchers for the walls that the kitties can crawl up. Bookshelves that can jump on that have toys all around it (but you have to buy the toys for it.) A bone fish toy that's like the fish toy already added but its just the skele version of it. CATNIP :D Make it pretty expensive, you could sprinkle it on the carpets and in the grass you buy. A really old box TV with antennas the kitties can mess with which ultimately make the channel change, the kitties can watch like flies or cartoons on it!! Kitty pools >:) Certain cats that like the water could jump around in the water, like the rare blue kitties and such! Anyway, theresa few other toys but that's just my thoughts! <3