Well, hopefully the parents of her Grandkids, will get her things for her home, for their kids. Since she is babysitting their, kids. That is their responsibility.
For me personally: I would not get things for the grandkids. This is "her" Retirement. So get something, JUST for her.
Maybe a gift cert, for a pedicure, a hair salon, a restaurant, a gas gift. cert. (since she will probably have to drive the kids around), a nice food basket, a camera (Costco has well priced ones), etc.
I would not want, the gift, to be correlated to "babysitting." But rather, that the gift be about her "Retirement." Because, retiring, is an EVENT, in itself. And it is special, for HER.
It not being about babysitting.
But about her as a person who taught for many years.
AND that, you appreciate her and LOVED her, for being such a great Teacher, for your Daughter.
Also, I would include something from your daughter. She can draw her a picture or include a photo of her. With something worded by your daughter.
Give her something, not correlated to babysitting.
But just for her.
Not a 'grandma survival kit.'
This is not about her being a 'babysitter.' But about her, as a wonderful person and Teacher.
For all you know, maybe she didn't want to retire just yet, but had to, to babysit her Grandchildren. Plural.
Thus, this is not her 'first' Grandchild.