What does she like to do? What are her hobbies? My ILs are generally good at getting gifts for me because my MIL is tuned into how I spend me free time and remembers that (well except when she buys me earrings and apparently hasn't noticed in 10 years that I don't have my ears pierced LOL).
Some gifts that I've really liked from my ILs: a bracelet with a charm representing each child, a funky tote bag with my name embroidered on it that I use as my gym and a overnight bag, a running hat and good quality running socks, a gift card to a sporting goods store so that I can treat myself to exercise gear, gift cards to my favorite clothing store, new cookie sheets because my old ones were an abomination, a nice roasting pan with a rack, a piece of jewelry or scarf that she thought would look nice on me, really nice & pretty salad tongs, etc. Obviously I like to exercise and spend time in the kitchen.
Does she have a kindle or other e-reader? Can you get her Amazon cards or iTunes cards so she can buy herself some books? Maybe an e-book gift card with a cozy throw would be nice if she's a reader (I know I'd like that LOL),