12 Letters that Did Not make the American English Alphabet -Page 4

Insular G
This letter (referred to as "insular G" or "Irish G" because it didn't have a fancy, official name) is sort of the grandfather of the Middle English version of yogh.

As Old English transformed into Middle English, insular G was combined with yogh and, as mentioned earlier, was slowly replaced with the now-standard "gh" by scribes, at which point insular G/yogh were no longer needed and the Carolingian G stood alone (though the insular G is still used in modern Irish).

That
Much like the way we have a symbol/letter for "and," we also once had a similar situation with "that," which was a letter thorn with a stroke at the top. It was originally just a shorthand, an amalgamation of thorn and T (so more like "that"), but it eventually caught on and got somewhat popular in its own right (even outliving thorn itself), especially with religious institutions. There's an excellent chance you can find this symbol somewhere around any given church to this day.