This paper describes recent research to create, manipulate and utilize positron, antimatter plasmas. One is the development of a method to extract cold beams with small transverse spatial extent from plasmas in a high-field Penning-Malmberg trap. Such beams can be created with energy spreads comparable to the temperature of the parent plasma and with transverse spatial diameters as small as four Debye screening lengths. Using tailored parent plasmas, this technique provides the ability to optimize the properties of the extracted positron beams. In another area, the design of a multicell positron trap is described that offers the possibility to accumulate and store orders of magnitude more positrons than is presently possible e.g., particle numbers >10¹². The device is scalable to even larger particle capacities. It would, for example, aid greatly in being able to multiplex the output of intense positron sources and in efforts to create and study electron-positron plasmas. This multicell trap is likely to also be an important step in the development of portable traps for antimatter. The third topic is a discussion of possible ways to create and study electron-positron plasmas. They have a number of unique properties. These so-called “pair” plasmas are interesting both from the point of view of fundamental plasma physics and for their relevance in astrophysics.