に限らず|にかぎらず

Means "not limited to X" or "not just X." It says that what is true of X is also true of a wider range of things or people.

Slightly formal but common in both speech and writing, such as news, descriptions of places or products, and explanations. It typically introduces a narrow case first and then widens the scope, e.g., 若者に限らず、お年寄りにも. It is close to だけでなく, but it emphasizes that the scope is not restricted rather than simply adding an item.

• 1.
  のみならずN2「のみならず」 is written-style and rather stiff; besides nouns it also attaches to verbs and adjectives (na-adjectives take 「である」), and it can open a sentence to mean "not only that." With nouns the meanings are close, and the two are often interchangeable in writing.
• 2.
  だけでなくN3「だけでなく」 attaches to nouns, verbs, and adjectives, simply stacking the second item on top of the first, and it can even set pros and cons side by side; 「に限らず」 attaches only to nouns and stresses that the range goes beyond them. When nouns are lined up to widen the range, the two are often interchangeable.
• 3.
  はもちろんN3「はもちろん」 treats the first item as a given and then adds more on top, and the second item can take 「まで」 to add a nuance of surprise; 「に限らず」 is more objective, merely stating that the range exceeds the first item. The two are often interchangeable, and 「はもちろん」 can also follow 「名詞＋格助詞」.
• 4.
  ばかりでなくN3「ばかりでなく」 attaches to nouns, verbs, and adjectives, while 「に限らず」 attaches only to nouns. With nouns they are often interchangeable: 「に限らず」 highlights widening the scope, with the first item as a typical example, while 「ばかりでなく」 highlights adding more of the same kind or going a step further.
• 5.
  に限ってN2「に限って」 means "of all things," "solely," or "limited to," narrowing the scope — the opposite of the expansion expressed by 「に限らず」 — so the two cannot be swapped. Besides nouns, its "of all things" sense can also follow patterns like 「動詞＋時」.
• 6.
  を問わずN2「を問わず」 follows nouns involving multiple variations, such as age or weather, or antonym pairs like 「男女」, and means things are the same whichever applies; it leans toward written style. 「に限らず」 follows a typical example and then broadens the scope with 「も」, so the two generally cannot be interchanged.

Like のみならず (more formal and written), だけでなく and ばかりでなく, it means "not only," but those also attach freely to verbs and adjectives, while はもちろん treats X as obvious before adding Y. に限って means the opposite, "specifically X," and を問わず means "regardless of," usually with contrasting categories like 男女 or 年齢.