I've got, I think, nine tarot decks, three oracle decks and two Lenormand decks.
My understanding is that, yes, Lenormand meanings are pretty set, and there's no great need to have multiple decks, however, there are an awful lot of pretty decks out there and it's probably not the end of the world to have more than one. There's also some decks which have extra/alternative cards (for example there's a few that have two versions of the Man and Woman cards) which can be useful for certain things, e.g. same-gender relationships, a pair of siblings, and so on.
I have one very 'standard' Lenormand (French Cartomancy with card inserts and kinda 18th Century type illustrations) and one called the Celtic Lenormand which has I think two of each of the people cards (I think including the Child card which isn't always included in alternate versions) plus, if I'm remembering right (I haven't used it a lot as yet, still getting to grips with Tarot so I decided to hold off on Lenormand for now) it also has a Cat card in addition to the Dog card (with its own meaning) and I think it has two or three options for the Bird card.
One point that's definitely worth considering with Lenormand cards is that, particularly when you're first learning, it can be really helpful to have very clear images so you can see at a glance that *this* card is the Letter while *that* card is the Key, and so on. So, some of the more arty decks may not be great for beginners. But once you've familiarised yourself with the system and got a good grip on it, you may find that you don't need quite such clear images and can look at something a bit more "out there".
For example, two gorgeous indie decks are the Moonshadow Lenormand
https://www.etsy.com/listing/207677660/the-moonshadow-lenormand-card-deck-by and the Diana Lenormand
https://www.etsy.com/uk/listing/219...-by-alyzen-moonshadow?ref=shop_home_active_12 both by the same creator. They're both lovely looking, but for me the Moonshadow is FAR easier to look at and instantly know what each card is, so (as a beginner) if I was going to buy one, it would be that one. On the other hand, if I do buy another Lenormand deck in the future, it will probably be when I've done a fair bit of study with the decks I already have, in which case I may be more comfortable with a deck like the Diana where I have to look a little harder at some of the cards. (Of course, quite a number of the Diana cards are pretty easy to tell what they are! But overall it has quite a few that I'd have to think about for a moment/read the name.)
