LETTERFONT from Allanson Computing is a utility program which will give you up to six type-styles on a 48K Spectrum. There is also the option to design your own. The type-styles available are Countdown, a modern hi-tech type face, italic, typeface similar to that of an old-style typewriter, bold, gothic and sync, based on the typestyle of the Sinclair logo.
The program can load any or all of those and works by altering the system variable CHARS at addresses 23606 and 23607. They are used to point to the character set, normally held in ROM.
When you want to design your own type-style you are presented with an 8 x 8 grid, as in the Horizons tape, and can use either one of the defined characters or start from scratch. You can also copy styles from one set to another. Details are included to save the styles and then use them in your programs.
The idea of having different characters is not new but this is a reasonable implementation; only three of the six sets will probably be of any use but the number you can create is infinite.