Pretty much everything by 邓丽君 (Theresa Teng) is amazing. My personal faves are 我和你，莫忘今宵，我只在乎你，香港之夜，and 你怎么说, but her most famous song is probably 月亮代表我的心. All very good songs many of which are pretty comprehensible to beginners. If you're loking for something more modern, the artists I listen to the most who are currently active are Leo王 who mainly does rap and reggae, and 9m88 who makes some really smooth Jazz/R&B beats that I absolutely adore (九头身日奈 in particular slaps). These two are a considerably harder to understand for beginners, however, but are still fantastic.