Aunt Lydia's Rug Yarn doesn't seem to be available any more, and it usually fell apart on me so I wouldn't recommend it anyhow.
Several folks have mentioned that Red Heart yarns wear like iron so they like it for blankets that kids carry everywhere. It is all acrylic, so it can be machine washed and dried, and some folks say it softens after washing.
Red Heart Grande' [that's supposed to be an accent], a bulky yarn, is intended for rugs and such. It is all acrylic, although color selection is limited. I haven't seen it in stores lately, but it is still available online:
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www.yarncollection.com]
Perhaps you could knit with a double strand of Red heart worsted weight yarn (available at most craft stores or departments, including Walmart, Hobby Lobby, etc.) to get the bulk you want for a rug. You would have a wider range of colors to choose from (than the Grande'), and it is available in large (16-ounce) skeins as well as the regular size (5-8 ounces).
I suggest you try a small rug (say, for the bathroom or back porch entry) to see whether you like the results and if it holds up. Let us know how it works out.
By the way, if I remember correctly the pattern books I have for knit / crochet rugs use double-strand worsted weight yarn. If you need info about these pattern books, please post again and I'll see what I have on file.