Many places; I'm currently using (which I haven't the foggiest idea who made), but it's not hard to find other lists.
At any time
before you scan the amiibo; if the villager has already been summoned, then it's too late to use the code for that day. The code remains active until you restart the game (or overwrite it with a different code swapping Curt).
It's a packed structure, so there's more data around; I could either include bytes from before the ID or after the ID, so I went with the option that allowed me to align the code to the nearest 4-bytes multiple.
BTW, if anyone wants to know how I made the code: I extracted the game files (using NXDumpTool as it allows me to navigate the already patched RomFS and only dump what I need), opened Bcsv/AmiiboData.bcsv in Toolbox, picked a villager amiibo at random, used SXOS to find where in memory it was, and created a code to replace the villager ID string for that amiibo.
Since I guess people will just keep asking for codes for the new villagers, here is the list (untested):
Code:
[Audie in place of Curt (Amiibo)]
08100000 474856C4 00003231 6C6F7701
[Cyd in place of Curt (Amiibo)]
08100000 474856C4 00003231 706C6501
[Dom in place of Curt (Amiibo)]
08100000 474856C4 00003531 70687301
[Judy in place of Curt (Amiibo)]
08100000 474856C4 00003931 72626301
[Megan in place of Curt (Amiibo)]
08100000 474856C4 00003531 61656201
[Raymond in place of Curt (Amiibo)]
08100000 474856C4 00003332 74616301
[Reneigh in place of Curt (Amiibo)]
08100000 474856C4 00003631 73726801
[Sherb in place of Curt (Amiibo)]
08100000 474856C4 00003930 616F6701
(Still laughing at people calling it the Curt code; I basically picked him at random.)