The sorting is automated.

  word_count = Counter(w for s in sentences for w in words(s))

  sentences_by_word = defaultdict(list)
  for s in sentences:
    for w in words(s):
      sentences_by_word[w].append(s)

  sentence_sort_key = lambda s: sorted(word_count[w] for w in set(words(s)))

  for w, _ in word_count.most_common():
    candidates = sorted(sentences_by_word[w], key=sentence_sort_key, reverse=True)[:5]
    for c in candidates:
      print(w, ':', c)
    input()

(Add epicycles for defining what a word is, what a sentence is, ensure the candidate sentences have varying lengths, keep track of which words and sentences were already seen...)

The final step of choosing one sentence and turning it into an Anki flashcard is manual.