3 of six patterns tried
Most available online and include Wendy's Original Mouse, Garter Stitch Variation of Wendy's Mouse, a rotund bobble eared mouse - knit in the round, another bobble eared mouse this one with I-cord tail (photo: far right), and another bobble eared (tail-less) mouse (photo: center) and the one that seems to be the favorite of my cats (though I prefer bobble ears to picot ears) is the silken braid catnip mouse (link to pdf; photo: left)
Yarns used: various scraps - all acrylic worsted weights, some with novelty yarn such as Bernat Boa held double strand with a worsted weight yarn. Fun fur is not recommended as it is too long and results in something that looks (according to my husband) like a rat with mange.
Comments: definitely knit with smaller sized needles than the yarn calls for - I think I cranked most of these out on US5 or 6 needles. Either pack the catnip in the middle of batting or other fabric to help prevent leakage, and stuff the mice firmly. I'll be knitting up more - and plan to do some felted ones too.