The `collections` module offers specialized containers that solve common patterns more cleanly than plain dicts/lists.
python
from collections import Counter, defaultdict, deque
Counter(["eth", "eth", "btc"]).most_common(1) # [("eth", 2)]
groups = defaultdict(list)
groups["stable"].append("USDC") # no KeyError, auto-creates []
q = deque([1, 2, 3])
q.appendleft(0)
q.popleft() # O(1), unlike list.pop(0)`deque` supports O(1) appends/pops from both ends, making it ideal for queues, unlike a list where `.pop(0)` is O(n).