To meet the growing requirement of servicing high-quality video contents, Alliance for Open Media (AOMedia) has recently released an open-source video coding scheme named as AOMedia Video Coding 1 (AV1). In this paper, we review its intra coding tools in details and evaluate their individual performance in On-Off tests. Our experimental results show that the additional directional mode and the recursive filtering achieve the highest Y-BDBR gain under all intra and random access configurations, respectively. The chroma from luma prediction saves significant bits in chroma channels. Additionally, the Paeth predictor performs betters for screen contents. Color palette prediction is seen effective for screen content sequence.