This paper presents research on semi-supervised learning (SSL) based on Vision Foundation Models (VFMs). To validate the effectiveness of SSL over rich unlabeled data with limited labeled data, we developed a new benchmark dataset and evaluated several SSL techniques. In particular, we found that Parameter Efficient Fine-tuning (PEFT) achieved comparable performance to SSL even with labeled data alone. Inspired by this finding, we revisited self-training, a simple SSL technique, and proposed a method for generating pseudo-labels for unlabeled data using PEFT models. To address the problem of noisy pseudo-labels, we proposed an ensemble of multiple PEFT techniques and a VFM backbone to generate more robust pseudo-labels, and demonstrated its effectiveness.