I can recommend a few really nice items from this site. If she is conservative, I wouldn't buy a gift card. My mum can be that way as well. A few things that I have bought my parents are:
Oil of Love original (there are tons of flavors/scents)
By far the best massage oil I have ever used. Tons of flavors and scents. Smells good, tastes amazing, and is perfect for couples who enjoy massages. Also has a slight warming sensation, but not overpowering.
Don't Stop by Booty Parlor
This is a lubricant/oil. Very pleasant to use, doesn't stain the bed sheets and washes off easily.
Anything by Shunga... their products will never fail you. They have soaps, oils, lubricants, etc. Most of their products have sexual enhancing ingredients and a warming sensation that isn't too strong.
There are tons of massage kits on eden. Massagers and massage kits can be great to have around the home. I have my hitachi wand which is great when my fiance is away and my back hurts.
I hope you find something! Please message me for more ideas if you need them!