Decided to see if I could remember the old conlanged alphabets I made back in high school, respectively named Uldanya and Fibbonacci. As the name would suggest, Fibonnacci combines each letter or number with the letter in front of it, i.e. a+b, b+c, etc. It doesn’t really have any rules aside from that, being a simple reskin of the existing English alphabet (although I never bothered to make capital letter versions, so I guess everything is just lowercase now.)
Uldanya, on the other hand, does have some rules. You can play sort of fast and loose with this, but in general any superfluous letters (thick, ending, and so on) are left off if possible, and things tend to be spelled phonetically, especially if it helps make the first rule possible. Also, letters are never left by themselves unless it’s a proper noun or something, so “I” becomes “ai” and “a” is spelt “ay”. In cases where the “u” or “n” symbols above the letters would denote 3 of the same letter (as in unusual) the third would be left off entirely, and any following that (if that ever happens) would recycle the process. I’d really love to find some way of making Uldanya into a working typefont but I have no clue how it could be done.