The companion website for the Cambridge textbook, Pronunciation Pairs, tells which sounds tend to be most challenging for speakers of each of 25 languages. There are also some useful exercises here for practicing each sound. (You can use them with or without the textbook). They consist of worksheet downloads, corresponding audio files, and answer sheets for practicing the vowel and consonant sounds that are most troublesome to English language learners.
Rachel’s English has hundreds of very clear, helpful, and engaging pronunciation videos for English language learners.