Who is the illustrator that illustrated the least amount of cards? List the format of play of the cards that he/she illustrated.
format of the cards refers to format; illustrator refers to artist; the least amount of cards refers to MIN(artist)
SELECT T1.artist, T2.format FROM cards AS T1 INNER JOIN legalities AS T2 ON T2.uuid = T1.uuid GROUP BY T1.artist ORDER BY COUNT(T1.id) ASC LIMIT 1