Nope! I have two spreadsheets I've been working on, one for all items and one just for the catchables that also tracks where/when they're available and if I've donated them yet.
I have a really good app called "ACNL Guide". It lets you keep track of collectables and villagers in your town. It also tells you special events and villager birthdays. I definitely recommend getting it for those of you who are able to.
Microsoft Excel sounds like a good idea though. Might try that some time!
Not really. Back when I used to hack my second GCN town, I would convert EVERY spot from EVERY acre onto Excel. For example, spots with grass would be green and spots with water would be blue. It took ages but it was worth it and made hacking the GCN game so much easier. Sadly I lost that file. I'm not the only one who did that too, BrianMp16 on YouTube also does it even to this very day (though he rarely uploads videos now). Also, there was this app for ACNL on iOS and Android but I don't use it because it has got a few issues and it's very time consuming checking what you have.
I have a word document for each of my towns that I write notes to help me remember what happened each day (useful when I attempt to blog, since I don't have time to blog every day). Every time I get something I just put it on a bullet point under a category with a note by it to say whether it's in my storage or not (but available in catalogue). If I come across an item or fossil in the game I just "Ctrl F" to find if I have it. I guess sorta like Excel but just using word pad lol. I don't like hoarding items so whatever I don't need I just trash it if it's orderable.
I use an app on my phone since my phone is with me 99% of the time so it's just easy to pick it up and mark something down. I like to know how many fish, bugs or art I have left to collect, it also helps you determine which art is genuine or not. The guide is really helpful c: I think it's available on both iPhone and android.