Hello Skulltip, thank you for explaining the concept.
You can change the standard ugBASIC font easily with the FONT LOAD command. The command converts any image into a matrix of characters, which are then loaded one at a time, from left to right and top to bottom. Once loaded you can use commands like PRINT, CHR(...) and so on.
Unfortunately, the MOB command is not implemented on all platforms, and moreover it is "deprecated": in fact, I have discovered that intelligent use by programmers of the GET IMAGE / PUT IMAGE primitives gives far better results. So I suggest to check if these instructions can be helpful. If you then use hardware that has hardware sprites, you can check if they have enough features for your needs.
Thanks again, and have a nice retrocoding!