Both Per VLAN Spanning Tree Plus (PVST+) and Per VLAN Rapid Spanning Tree (PVRST) protocols allow for a spanning tree instance for each VLAN, allowing for the location optimization of the root bridge for each VLAN. These are Cisco proprietary enhancements to the 802.1d and 802.1w standards, respectively.

Rapid Spanning Tree Protocol (RSTP) is another name for the 802.1w standard. It supports only one instance of spanning tree.
Spanning Tree Protocol (STP) is another name for the 802.1d standard. It supports only one instance of spanning tree.