Paramecium is a simple protist and divide asexually into two. This division is called binary fission.
Plasmodium is capable of producing cysts during unfavourable conditions. Within a cyst, a cell divides multiple times. When favourable conditions return, the cysts breaks to release all the individual cells. This is called multiple fission.
Yeast is a simple and single celled organism which divide by budding.
Spirogyra reproduce by fragmentation.