The modern pattern weights I have seen are little bean bags, which are fine (made by Dritz), but I already had six of the white plastic ones, which I love. This is what the Dritz variety look like.
With my larger blocks, six pattern weights were just not enough.
I received my first set of white, plastic, "vintage" pattern weights in the early nineties as a wedding gift from someone who thought I would use them in garment construction (as if I make garments anymore...).
They didn't grab me at the time...I even lost one of them in our reclining chair when I opened the package. I put the remaining five away and the sixth one remained buried somewhere in that chair for over 20 years.
Then, I realized how great they were for applique prep!
I finally turned the recliner over last spring before selling the recliner in our moving sale, pulled the Velcro'd fabric panel away from the back of the chair frame, and dug around in there until I found the weight...it was like hunting Easter eggs!
What's lurking in your furniture?
I found the missing pattern weight, $1.28 in change, and 8 cat toys. I still had my sweet Weasley then, and he was thrilled with "new" toys, as was I.
If I had been at a garage sale, I would have looked over this little box of "gems" just thinking it a travel box for a bar of soap. My original set of six came in a baggie, not a box.
I have a few that my friend Bruce made for me that work pretty well, but something a little heavier is needed for some blocks. I don't know what is inside to make them so heavy for their small size...BB's, lead fishing weights, pieces of Jimmy Hoffa.
If you are looking around on eBay, Etsy, or your favorite online used stuff site for this same sort of thing, I had luck searching for "vintage pattern weights." One day they are there, then not, then another set there...it is kind of weird!