If you want to customize your font, but the characters are outside the Ascii range, you can use this tool:codehz/minecraft-unicode-font-texture-generator-online(Only tested in Chrome , Edge.)
1. TYPE font name(because web page has no permission to list your system fonts...)you can just pick up from Notepad - format - font.
2. Choose a font size
3. Choose grid size, it should be greater than font size, (a char's grid width and height, should be 16, 32, 64, 128,etc)
IMPORTANT: grid size is 16 mean 256x textures pack, because a minecraft's font texture has 16x16 charactor...so if you type some like 1024, it will be crash your browser(or just that web page).....
4. Y-axis Offset used to fine tuning the font position in Y axis
5. You can change the pack_format to adapt your minecraft version, if you dont know what is pack format, you can just leave it 1.
6. DO NOT MODIFY other option UNLESS YOU KNOW WHAT YOU DO.
7. Press "Generate!" button, it will start generate the texture pack.
8. You can press "Stop!" to stop process....
9. If all goes well, you will get a zip file. just move it to your minecraft reasource packs path, and than you can choose it in menu.
NO ASCII FONT GENERATED! it may be added lately...it will NOT change ascii font, BUT you can choose Force Unicode Font in your language setting..
HD(large than 16x(256x)) Font may be not work in some version, maybe you can use MCPatcher or Optifine HD to fix this issue...
I have a plan to port it to Pocket Edition, but now it does not work, because minecraft pe's textures pack's format changing is too frequently, And I have no idea to adapt what beta version......
It also have "C++ Version"....it faster than web version, and have more functions, but it need to be compiled before using, and only officially support Linux.....
(Sorry for my poor English, I have try my best to adjust my grammer.....)