Updated June 7, 2019.
Filet Lace most often refers to a form of lace which has an open grid with the filled squares of the grid making a pattern. A version of crocheted lace that looks similar to this traditional lace is the kind most commonly found today, called Filet Crochet.
There are tons of filet crochet patterns out there, both on the Web and in books, with graphed patterns that can easily be converted to needlepoint.
Traditionally this lace is done in white or off-white, but recently I have seen it done in colors as well. This creates additional possibilities for needlepoint.
There are a couple of approaches to converting filet crochet to needlepoint, one using colored canvas and one using different stitches to make the pattern on white canvas.
The open method is pictured above in a partially stitched design taken from an Internet pattern of a swan. The effect of the lace comes from using colored canvas and cream threads. The grid is made using straight stitches and the filled squares are made using Mosaic Stitches. You could also scale up this method by using Scotch Stitch for the filled squares. The picture below shows how they both look on black canvas.
One place to find lots of free filet crochet patterns is the Antique Pattern Library. An example of one of these vintage patterns in below.
Another method to adapt these patterns begins with a white canvas and uses framed Smyrna Crosses to create both the grid (the frame of Tent Stitches), the pattern (the white Smyrnas) and the fabric showing through the lace (the colored Smyrnas).
It’s another great form of adaptation for needlepoint that helps you create original pieces.