Well, leather lets you off the hook by buying a nice belt, and willow . . . uh . . . you can weave a wreath out of willow branches. Or buy a basket made of willow. Platinum is sure going to set you back, though.
But don’t most people who buy their anniversary gifts based on the themes on the list use the modern list (Wikipedia has traditional and modern lists here: https://en.wikipedia.org/wiki/Wedding_anniversary .) Not that the traditional list isn’t acceptable, but the modern list exists because the traditional list can be difficult to buy from (Just try to buy something ivory for your 14th anniversary without running afoul of the law.) or just make for boring presents (Aluminum. Thanks, baby. It’s . . . beautiful.). The modern list controls for these problems (Well, maybe electrical appliances on the fourth anniversary aren’t the world’s most exciting gifts — unless you pick them up at a non-leather-exclusive fetish shop.). And the possibilities for modern list anniversary #24, musical instruments, are endless. Tuba? Harmonica? Matching engraved kazoos?