I don't think it happens often, but I did just see a collection that had been brought back by popular demand (though I cannot recall the name of it). I don't know how long ago the fabrics you mentioned went out of print, but if it's only a few years there is still a good chance you can find something. Depending on who is selling, you may pay more or less than you would if it was a current print. Etsy/eBay will likely be more, but sometimes you can find a small quilt shop that has a bit of stock left in their online store on sale or clearance because it's "old stock." It can take a lot of searching. A lot of the fabric I have bought recently has been out of print for awhile, some going back to 2008.
You might also try emailing the designer, if they indicate that they are open to contact. I had emailed one designer asking a question about their fabric and if they knew of any places where it still might be sold. They offered to sell me some from their own stash at a very reasonable price. Don't expect that kind of response, but it's also a possibility. Good luck on your quest!