USA IELTS & English tests - Study without IELTS

What other English proficiency exams besides IELTS are accepted for admission?

Is it possible to get an IELTS waiver based on my academic scores and graduation year in UK/USA for a MBA?

Is Ireland a good option for study abroad with flexible spouse policies and no IELTS requirement for spouse for a PhD?

Is there an option to get a waiver for the English proficiency test requirement in UK/Netherlands?

Are there other countries besides the UK that offer post-study work permits or stay-back options without IELTS in Germany/Singapore?