More or less an idea that popped up into my head regarding two other threads that have been made, such as the lowest numbered route you haven't been on, and the lowest numbered route you haven't clinched. However, there's a lot of people on this forum (including myself) who are also on the side of picture taking, and I do think this would be an interesting topic.
A couple of things I do want to bring up real quick is that there are a couple of routes in Europe that are numbered 0 with legitimate signage of them, but for all intensive purposes, 1 is the lowest possible route number. If you happen to have a picture of a route numbered 0, that's cool too. The other thing is that I have a spreadsheet with over 1300 different numbered routes that I have pictures of dating back to 2016. I do have county roads included in the sheet, and this also includes certain counties that just number all of their roads with a blue pentagon (or something similar) instead of properly naming or signing them. I'm totally fine with anybody including county roads as legitimate route numbers.
With that being said, after extensively looking through and logging all of the pictures I've taken, the lowest numbered route I don't have a picture for is 122. The only route numbers I'm missing below 200 is 122, 153 and 168. 122 is about a two hour drive northeast of where I live, 168 is a bit farther than that (north of Jonesboro) and 153 is in Arkansas county east of Stuttgart.