といったらない

1. 1Emphasizes that a quality or feeling is extreme beyond description, whether positive or negative.Ex. 1
2. 2In the past form といったらなかった, it describes something that was extreme on a past occasion.Ex. 2

Voices the speaker's strong, emotionally charged evaluation of something so striking it seems beyond words. It often follows a ～さ noun or a noun phrase describing someone's appearance, a state or an experience. It can evaluate other people or outside things, not just the speaker's feelings. It is common in lively speech and expressive writing, and is less formal than の極み or 極まりない.

• のなんのってN1「のなんのって」 has a similar meaning but is more colloquial. It attaches to the plain form of adjectives and verbs, not directly to nouns, and is often followed by a result or simply left unfinished. For example, 「寒さといったらない」 can be rephrased as 「寒いのなんのって」.
• 極まる・極まりないN1「極まる・極まりない」 attaches to the stem of な-adjectives or to 「…なこと」, not to nouns or い-adjectives. It is mostly used for negative evaluations and sounds stiff and literary, whereas 「といったらない」 works for both positive and negative things, is neutral in register, and carries a strong exclamatory nuance.
• の極みN1「の極み」 also expresses that something has reached its peak, but it attaches only to nouns (mostly Sino-Japanese ones like 「感激」 or 「贅沢」) and cannot take adjectives. It is formal and literary, typical of speeches or writing, and using it for small matters in casual chat sounds exaggerated and stiff.
• 限りだN1「限りだ」 attaches only to emotion words such as 「寂しい」, 「残念」, and 「感激」, expressing the speaker's own feelings in a formal, somewhat literary tone. 「といったらない」, by contrast, is a neutral-register hyperbolic exclamation about the nature or state of something.
• てたまらないN2「てたまらない」 describes the speaker's own emotions or physical sensations being so strong they are unbearable, and it attaches to the て-form. 「といったらない」 mostly exclaims about the nature or state of something and can attach to nouns; to exclaim about an attribute like how high a mountain is, only the latter can be used.
• てならないN2「てならない」 expresses the speaker's own uncontrollable feelings, sensations, or thoughts, attaches to the て-form, and leans literary. 「といったらない」 exclaims about the extreme nature or state of something, usually attaching to nouns or the さ-form of adjectives, so the two are generally not interchangeable.

てたまらない and てならない attach to the て-form and describe feelings or sensations welling up inside the speaker, and 限りだ states the speaker's own emotions (嬉しい限りだ); といったらない, by contrast, can also evaluate other people's features or outside things. の極み and 極まる・極まりない are more formal and literary, while のなんのって is a colloquial way of stressing extremeness.