Haha, long is the answer for me!
I don’t use lists so much anymore but rather just word documents/the notes app on my phone- I used to live by listography but that’s not so much the case anymore.
I have a list of words names (some outlandish, some more useable) which I made years ago, and has over 800 names on it. I also have a compiled list of the combos I’ve made (again, from years ago, so it’s outdated now since I haven’t kept it up) which probably amount to 100+ combos for girls and the same for boys.
More currently, I have a document with all the combos I’m playing with at the moment (including the ones in my user card) - for girls this is at almost 50 first names, with between 10-40 two-middle combos that I’ve thought of and considered for each name. I use the same format for my boys’ combos, except I only have around 25 first names. This is all alphabetised, so it’s quick for me to access and look over, as well as add new combos as I think of them. However, it is worth noting that a lot of these combos aren’t something I’d use in real life, if given the chance- I just like playing with names for fun.
As for having an actual shortlist, I’m far from having any children in real life, if at all, so I just haven’t really bothered. If I did decide to have children in the future, I’d like to adopt- and not necessarily an infant, so likelihood is I might not be naming my future children anyway, which isn’t something I’m bothered by.
The closest thing I have to a shortlist is when I answer those ‘What would you name quadruplets?’ threads, because I do have somewhat of an idea of my top four/five/etc, it’s just never written down/particularly stable since my favourite combos are constantly changing.