yk the color palette? that's pretty cool, righ? now, that applies to colors. in theory you can have infinite, just not at once :)
now, ever wanted to build a ui, but turns out you're missing some super weird character? you could use a resource pack, sure, but what abt servers? ok so basically-

Not sure if I like the syntax, but something like this. The 1px border is also included.

term.setPaletteChar("\x90", {
  "        ",
  "        ",
  "     X  ",
  "    XX  ",
  "        ",
  "        ",
  "  XXXX  ",
  "        ",
  "        ",
  "XX  XX  ",
  " X      ",
})

^ fyi, this isn't supposed to represent anythig.

This would allow for somewhat higher resolution, but still be locked to oh so many characters. This could be treated as a limited graphics mode ig, that doesn't have the issue of having to send huge amounts of data to the client, as it's all just one of the 256 characters after all. idk.