Isabella,
In Sydney I buy a brand called "So Gentle" at IGA supermarkets. It's in a small packet, just a bit bigger than the purse size Kleenex packets, so it won't jump out at you on the shelf -- just slowly browse through all the washing detergent products and I'm sure you will find a colour catcher of some brand there. There are 10 sheets in a pack, and I use a sheet 2-3 times each, not the once it says on the packet. It's good for normal clothes washing, to catch any loose dyes/ colours, especially if you are mixing darks with lights as I do all the time since I am washing for only 2 people.
If I was washing a quilt I would only use a brand new sheet.