Just give it a floor run, see if it plays.
My youngest cat likes to chase the little pieces of cat food when we throw them across the tile kitchen floor. May not work for everyone, but she sits at the food bowl and cries for you to throw it for her.
One toy one of my cats consistently goes back to is a ball about three inches in diameter made of some sort of fluffy material (wool, maybe?). Sewed into the ball are pieces of plastic foil that make a crinkling sound when it’s picked up. This cat carries that toy just about everywhere. She flicks it up in the air with her mouth and bats it down with her front paws.
The only thing spud plays with is an empty plastic bag. Best toy ever according to him (he told me so).
Cardboard boxes come in a very close second.
A piece of string that he can chase is a distant third.
I find that the best toys are the ones that are exact opposite of the $50 in toys you purchased for that specific purpose.
My cat’s favourite type of toy is small, furry, goes squeak when pounced upon and runs like hell if he gives it a chance to get away.
He’s not generally interested in any inanimate toys for more than a minute or two. We’ve never tried him on catnip - I don’t want my cat turning into a druggie thanks. 
Cats are all totally different; you never know what they’ll like or not like. Our cat, for example (the “fuzzy black land shark”), completely disregards all entertainment options except for these three:
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The mail. Seriously. He likes chewing the corners off the envelope to the gas bill. He’s weird.
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Kitty Hoots. Don’t know if you’ve seen these, but they’re stuffed characters (fish, mailman, Bill Clinton) with a wad of catnip embedded in the center. Our cat goes nuts for these; he’ll play with one for an hour, and then it’s soggy with cat drool.
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Laser pointer. Best Cat Toy Ever. We just have to be careful not to flash it in his eyes, and we can get him running all over the house, the yard, jumping up against the wall of the neighbor’s house, etc.
Based on #2, I don’t know what your handmade mice look like, but I’d suggest a little personalization. Maybe draw glasses on one and sell it as a “book mouse,” or a tattoo on another and call it a “biker mouse,” and so forth.
Shan’s favorite toy that’s actually a cat toy is a squeaky catnip mouse on a fishing-pole like stick and line. His other favorite toy is a milk cap ring. He will also occasionally play with his squeaky catnip mouse and his squeaky catnip hedge-hog-looking-animal (both not on the fishing pole). All other cat toys he ignores.
Well not totally. He has a furry mouse that I can pull the string and it will scurry for about 5 inches. If I could find a furry mouse that scurried around for a longer period of time, I think he would love it. That’s what brought The Demon Mouse into the house, but It just terrified him, so It got shipped out of state.
One toy that surprised me in its appeal for my three cats appears to be two closed plastic tubes, wrapped in wool, and tethered together with another length of wool.
Inside the tubes there is something that makes a rattle, this must be quite small from the sound of it, and the noise is just enough to make them go for it. I’d guess that they used a few dried seeds or something.
It is very light, the tubes are about three inch long, and perhaps 3/4 inch diameter.
The wool that is wrapped around the tubes is glued on with impact adhesive from the look of it, and the tether goes rigth through the tube and is held on by a large knot.
The tether is about 3 feet long.
The tubes are very light and squashable.
It seems an unlikely looking toy but they just love it, or what is left of it, following a few months of pouncing, throwing, stalking and tugging.
where do i place my order green bean?
winkin the wonderful likes to bat "winkin"balls around the house.
nod the naughty likes bottle tabs/rings, and toys that have long tails that i can wiggle on the floor for her.
malenka the miraculous likes anything.
all three love plastic straws with the paper on.
I can’t honestly recall if my cats have ever had a catnip toy. They’ve decided that the best toy ever is something I rigged up for them out of laziness. Though, I’d probably buy one if I knew a doper was selling them 
For some reason, my brother ended up being given a bamboo rod to him by our Great-grandfather. It has never had any purpose whatsoever, but it did give me an idea…they’ve always enjoyed playing with the “fishing” type toys, but playing with those require a human presence. So I jammed the bamboo rod into the bookcase, under the heavy books, in far enough so only 4 inches or so sticks out at an angle safe for sleepy humans to pass. Then I tied one end of a boot lace to the rod, and a toilet paper roll to the other end of the lace. The lace and tube dangle enticingly, so they now have a toy they’ll play with themselves, usually when it “attacks” them and their tails as they walk by
Hey, if you have some left over, or have more made by early January, bring 'em to the MegaFest. I’d love to see them. God knows Scooter needs more toys to knock under the couch.
The feature I look for the most in a cat toy is…
durability.
My cats Ruckus and Havoc will rip apart any store-bought cat toy within 10 minutes. I have yet to find one that they don’t shred.
My top ten cat toys…
- Laser pointer.
- Empty brown paper bag with a hole cut in the bottom. (Try it!)
- Rabbit fur fake mice.
- Newspaper.
- A large clear marble.
- A dangled dish towel.
- Cardboard boxes.
- The plants.
- Any body part that moves under the covers…
10.The Christmas tree.
I just now bought a toy which I’m wondering whether it’s a little cruel.
It’s a plastic ring, about 12" across, with a ball inside on a track. Kitty bats the ball, but can’t get it out.
Am I causing psychological damage?
I also got them a wool sheep with a bell, and they’re ignoring it.
My cats still play like kittens and they are ten. They love catnip. I usually try to have catnip toys for them, and toys with out.
Harley is pickier about what he’ll play with, he likes the catnip and toys on a wand, and a tennis ball that he stole from me (I bought it for a dog).
Tawney will play with just about anything, but her two favourites are those tiny little furry mice and this one ping-pong sized ball. It’s covered in a carpet-y type cloth, has a feather sewn on and something rattles inside. She loves this thing.
They both love boxes and bags, of course. I read in a cat book once about a toy that I’ve made for my cats a few times. Get an old kleenex box (I like the longer flatter kind rather than the tall square ones). Tape up the opening so it’s just big enough for a paw. Drop in a walnut and give to the cats. They’ll spend hours trying to get at the damn walnut!
Masonite, we have that ring too, and I don’t think it damages the cats psychologically. They just ignore it after awhile. Mauvaise, we make the kleenex box toys for our cats, too, and they just love it. They like to fish things out of things, it seems.
As for the catnip, my cats have never had catnip and never will - it seems like a drug to me, and I just don’t approve of it. My cats get lots of fresh honeysuckle cuttings, though, which they absolutely love, but it doesn’t make them seem stoned like catnip does. Maybe you could put honeysuckle in some of the toys as an alternative to catnip.
One thing I’ve noticed that seems to be true of most cats - they love smelly stuff. I have an old dishrag that I used to clean up some fridge crap, and the cats roll all over it and sleep on it. I don’t know if you want to go as far as making smelly toys for cats, but they do seem to like smelly. Maybe store the toys with old shoes, or something - they like smelly shoes too.
And both of our cats like dangly things. The long tails are a great idea - dangling them from a stick would also work for my cats.
Cats love soccer on the tele and TV aquariums, but they do not care for Life with Bonnie.
featherlou, they’re bored with it already. I’m going to have to try that kleenex box-with-a-walnut-in-it.
- Irregularly-shaped translucent plastic “pebbles” (kind of like deformed marbles).
- A nice hank of scratchy rope with a mouse-sized knot in one end.
- The plastic milk jug circles mentioned above.
- Crumpled aluminum foil, preferably with a jingling or clacking item in the center.
- Brown paper bag.
- Box, partially closed as if to discourage cats.
- Refractive ribbons on a stick–one cat used to do backflips while chasing this.
- Kitty Hoots, as above, but generally not other catnip-stuffed toys.
- Bathmat.
- Ball-on-track.