You can print graphics and use different fonts from the iSeries by using an AFP type printer file(compile your printer file source with *AFPDS in the printer device type). By using AFP Utility (STRAFPU) you can create and modify an overlay for you printer file.
You can display GDDM graphics on a 5250 graphics workstation (or emulator). The last one I worked with was the old DOS Client Access emulator. I’ve often missed those after they were no longer distributed. I’m not aware of any 5250 graphics emulators that are still available. And I’m pretty sure that you’re unlikely to find a physical terminal to use.