Token Bucket: Bucket holds tokens. Each request takes one. Tokens refill at a fixed rate. Allows bursts.
Leaky Bucket: Requests enter a queue that drains at a fixed rate. Smooths traffic but may delay requests.
Fixed Window: Count requests per time window (e.g., per minute). Simple but allows x burst at boundaries.
Sliding Window Log: Store each request timestamp. Count requests in last N seconds. Accurate but memory-heavy.
Sliding Window Counter: Combine fixed windows with weighted average. Good accuracy and efficiency.
Token bucket is most common. Sliding window counter is a good alternative.