Answer
Five, ranked by what each one gives up.
- Wave spring — the same load in roughly half the height, with comparable deflection. The standard substitution when a housing has grown too tall.
- Belleville / disc washer — very high load in almost no height, but very little travel; stacks are used to buy back deflection.
- Wave washer — a single-turn ring, correct for simple gap closing and not for controlled preload.
- Elastomer or O-ring — inexpensive damping, but it creeps and is temperature-limited.
- Gas spring — long stroke and near-constant force, at a far larger installed size.
Where the cavity is fixed and both a load and a deflection are specified, the wave spring is usually the only one of the five that satisfies all three constraints at once.