~とあって indicates a reason for the following situation. More formal than から/ので. Often used with factual reasons that lead to a natural consequence.
犯人はいまだに逃走中とあって、警察は捜査を続けている。
With the criminal still at large, the police are continuing the investigation.
~であるのみならず
~であるのみならず is the full formal form of のみならず. Means 'not only is...but also...'. Used in essays and formal writing.
彼は天才であるのみならず、努力家でもある。
He is not only a genius but also a hard worker.
~ときたら
~ときたら expresses strong feeling/complaint about the topic. Often negative. Very conversational despite being N1 grammar.
この問題ときたら、私には解決できない。
When it comes to this problem, I can't solve it.
~だけに
~だけに means 'precisely because.../all the more because...'. Emphasizes that A is the reason for B. Often used when the reason is obvious and strengthens the result.
この仕事は危険なだけに、誰もやろうとしない。
Precisely because this job is dangerous, no one tries to do it.
~とはいえ
~とはいえ means 'although.../even so...'. Used to concede a point before stating a contrast. More formal than けど/けれど.
彼は貧しいとはいえ、幸福そうだ。
Although he is poor, he looks happy.
彼は貧しいとはいえ、他人を見捨てない。
Although he is poor, he doesn't abandon others.
~だからといって
~だからといって means 'just because...doesn't mean...'. Used to deny that A necessarily leads to B. Often with とは言い切れない.
彼は金持ちだからといって、幸せだとは言い切れない。
Just because he is rich, you can't definitively say he is happy.
~だけ~ても
~だけ~ても means 'no matter how much.../even if...'. Emphasizes that despite doing A to the fullest, B doesn't happen.
この薬は飲むだけ飲んでも、効き目は保証できない。
No matter how much of this medicine you take, effectiveness can't be guaranteed.
~でありながらも
~でありながらも is an emphatic form of でありながら. Means 'even though.../despite being...'. も adds emphasis to the contrast.
彼は金持ちでありながらも、友人がいない。
Even though he is rich, he has no friends.
彼は社長でありながらも、従業員の話を聞く。
Even though he is president, he listens to employees.
~にあたっては
~にあたっては means 'at the time of/when...'. Used for occasions, events, or starting something important. は adds contrast/emphasis.
海外支店の開設にあたっては、現地の法律を調査した。
When it comes to opening the overseas branch, we investigated local laws.
~でありながら
~でありながら means 'despite being.../although...'. Formal. Contrasts status with generous behavior.
彼は金持ちでありながら、人を助けることを惜しまない。
Despite being rich, he doesn't spare effort to help people.
彼は学者でありながら、芸術にも造詣が深い。
Despite being a scholar, he is also deeply knowledgeable about art.
~をよそに
~をよそに: 'indifferent to / ignoring others' concern.' N + をよそに.
世間の批判をよそに、企業は計画を強引に推し進めた。
Indifferent to public criticism, the company forcibly pushed the plan forward.
~んばかりに
'As if about to / looking as though one might.' Classical negative ん. Vない stem+んばかりに. Literary.
彼は感動で言葉が出なんばかりの様子でしばらく沈黙した。
He fell silent as if words might not come from deep emotion.
~極まりない
'Extremely / in the extreme.' Na-adj+極まりない or Na-adj+極まる. Very formal, often negative nuance.
締め切りを無視するとは無責任極まりない。
Ignoring the deadline is extremely irresponsible.
~手前
'Because of one's position/face/pride.' The speaker cannot act freely because of obligations from having declared or done something. N/Vた+手前.
部下に模範を示した手前、自分が規則を破るわけにはいかない。
Because I set an example for my subordinates, I cannot break the rules myself.
~しかるべき
'Appropriate / proper / as it should be.' Used to describe what is proper or fitting given the situation. しかるべき+N, or しかるべきだ.
事故の被害者にはしかるべき補償がなされるべきだ。
Appropriate compensation should be provided to accident victims.