Since the weather is starting to turn warmer, I’d go for something outdoors-ish - bubble makers are always a big hit, sidewalk chalk, walking toy/babydoll stroller, sprinkler for the garden hose, etc.
I vote for the book too. I think Pat the Bunny and The Velveteen Rabbit are both available in board books and would fit in with the bunny theme. DK books are available in board books and the kids in my world loved them from a young age.
Another suggestion, to add to CCL’s wheelbarrow one: kid versions of garden tools are available (in plastic) for next to nothing. She can “help” Mom or Dad in the garden or just pretend on her own.
Get her Dr Seuss’s Fox in Socks, and her parents will hate you forever. It’s a read aloud book, full of tongue twisters. My daughter loved it when she was a toddler, and insisted on having it read to her at least once a day. I used to be able to recite the whole book from memory.
Besides the fun of watching a parent critically fail at pronouncing words, it can introduce the concept of rhyming words, and the concept that changing one letter in a word will make it a completely different word.
Since when did Easter become about giving presents?! 
It’s not about giving presents, but giving children small gifts and candy is one of the ways it’s often celebrated. These gifts are usually put into a basket (creatively enough, it’s called an Easter basket) and are ostensibly left by the Easter Bunny. It’s like little kids putting their stockings out for Santa.
Good grief.
Ooh, ooh - bubble mower!
I make an Easter basket for my kids, and I usually include one $10-$20 toy, too. My kids aren’t big candy-eaters (yes, they’re weird) so I try to substitute other things for chocolate. I fill the eggs with peanuts or cashews, and since I have boys, I have included small toys like Matchbox cars, Pokemon cards, etc. It’s wasteful to buy $20 in candy they won’t eat.
There several good suggestions here. I would like to suggest what not to get. For the love of Pete do not get anything that makes noise on it’s own. No singing planes, cars or helicopters (we have one of each). No musical books. Nothing by that certain ‘baby genius’ company. (I have developed a nervous tick to Handel’s Water Music)
I could say this request is supported by science. That children need to develop play skills and imagination. But even if I had a cite for this, that’s not the reason. I’m speaking for her parents. To quote the Grinch “…all that noise, noise, noise…” The same little sayings; the same poorly rendered classical music snippets; over and over day after day. Three or four of the cursed little toys going off at once create a type of dissonance that the CIA could put to use at Guantanamo. They also have a lovely habit of going off all on thier own at 3:00 AM. There’s nothing like waking up in the dark hearing a high pitched voice saying “Let’s be friends”. It really brings home that Twilight Zone type horror.
So in brief let me say: ‘Won’t somebody please think of the parents.’…a get something nice and quiet and soft.
I second the recommendation for Sandra Boyton books. They’re wonderful and fun.
For Jimson Jim I will say - the only time to buy noisy toys for your friends kids is when you’re absolutely sure you’re done having kids of your own and they’re all grown up. Revenge is a horrible thing 
I like the books, or an Easter basket full of a bunch of tiny gifts ($1-$2) that are individually wrapped, so she can open them. 18 month olds can open gifts.
And I got my two year old niece a keyboard, Jimson Jim. Sorry. In my defense, the parents did recommend it!
I’ll second the animals. My daughters are 3 and 4 1/2, and have played with theirs every day for the last couple of years. We like the ones by Schleich. Girls like to play family, so get a baby animal and a matching parent or two. Target has a good selection of these.
Some nesting cups for playing in the bathtub might be a good choice, and look nice in an Easter basket.
Note to self: Give this guy a whole family of Furbies. With batteries already installed.
Someone gave you Psycho Puppy, didn’t they?
We have it too. A few days ago it said out of bloody NOWHERE, in its best simpering girlie voice, ‘Soooo BIG!!!’
Which is disturbing on just so many levels.
Oh, and Widget is only 9 months old so it’s probably very different, but we currently like a book called ‘Calm Down, Boris!’ It has a hand-puppet monster built in.
I got my niece an entire percussion set when she was 2–hand drum, tambourine, castanet, maracas, and the little scrapey thing. I’m not the least bit sorry, either. Anyone who changes the rules of basketball so you get triple points for banking a shot of his sister’s head and whoever makes her cry, wins…that sort of person deserves a 2 year old with a drum set.
The 18th month old just got here. I’m seriously considering getting here one of those puzzles with the large puzzle pieces. She’s fascinated by my fridge magnets, she keeps taking them off and trying to put them back where she found them.