For practicing:
https://agendaweb.org/exercises/grammar/comparison/superlative-adjectives.htm;
https://test-english.com/grammar-points/a1/superlative-adjectives/;
https://test-english.com/grammar-points/a1/superlative-adjectives/2/;
https://agendaweb.org/exercises/grammar/comparison/superlatives-1.htm;
https://agendaweb.org/exercises/grammar/comparison/comparative-superlative-4.htm;
https://www.focus.olsztyn.pl/en/comparative-adjective.html;
https://test-english.com/grammar-points/a1/superlative-adjectives/3/;
https://www.english-4u.de/en/grammar-exercises/comparison-superlative.htm;
COMPARISONS:
https://agendaweb.org/exercises/grammar/comparison/degrees-comparatives.htm;
https://agendaweb.org/exercises/grammar/comparison/positive-comparative-superlative-2.html;
https://agendaweb.org/exercises/grammar/comparison/comparative-superlative-adjectives.htm;
https://agendaweb.org/exercises/grammar/comparison/comparative-superlative-3.htm;
https://www.englisch-hilfen.de/en/exercises/adjectives_adverbs/adjectives_comparison_sentences.htm;
https://www.ego4u.com/en/cram-up/grammar/adjectives-adverbs/adjectives/exercises.