hope you find something she likes. Mine - well, we all have our favourite toys - and they are all different.
Cheapest and yet often best is as Helen suggested. Foil balls. You can make them as big or as small as you like. I have several who are ball fans (and others who don't care for them at all). I don't know what they are called 'officially' but we (i.e. me and the kitties) call them 'bouncy balls'. About 2/3 the size of a ping-pong ball. You sometimes get them (here anyway) in packages with the kids game of jacks. They are wonderful. Small enough that 'we' like to carry them around in our mouths. And fantastic to play with. If playing with a human - well, they bounce terrifically! But even if playing alone - they ricochet wonderfully off things with only the slightest of paw pushes, and then the chase is on! One of us also likes to bring them into the bathroom when I am bathing, drop them into the bath water, and then 'go fishing' for them.
For those of us not into balls ... mice. Not the catnip mice one sees constantly. No. These are small things (about the size of a bouncy ball around the 'waist' and maybe 2 inches long) but they look so real. And all my kitties love them. There are a lot of larger versions out there -with and without feathered tails (sigh!) but while we hate those ones, we adore the little mice. Even my lovely, little, totally shy and retiring Niome comes running and stands up to get one of these mice when I bring home a new 'stock'.
Sadly I don't know who makes them. I can get them in packages or out of a 'jar' at the pet food store. But if you are interested, I'll take a closer look when next there.