The images are free for personal use, though the artist requests that you donate time or money to the American Diabetes Association. There are a variety of ready to use tiles, borders and sets. You can find Celtic Accent graphics, and some lovely Celtic borders.
Bradley W. Schenck provides a variety of knot designs, gripping beasts, and interlace designs, including tiles and background images, in a Celtic style. Don’t forget to check out his store—there are some lovely Celtic inspired mugs and tiles (and other stuff) for sale. Mr. Schenk has neither slavishly copied medieval manuscripts, nor used scanned in tracings; his is a new take on an ancient style.
Reed Mihaloew offers not only art (various sorts of knots, interlace patterns, and tiled backgrounds), but instructions about creating your own Celtic art, and support materials in terms of bibliographies and background information.
Cari Buziak (who uses the Celtic computer, a Mac) offers both commercial art prints and clothing, and a selection of her own Celtic style clip art and cards, and stich and beadwork patterns as freeware. In addition to some beautiful art, she also offers information and tutorials.
Howard Oliver offers a variety of Celtic inspired knots, graphics, web page sets, borders, arrows, and buttons, free for non commercial use. See his terms. Mr. Oliver makes interesting use of textures in a number of his images.
Curiousity Stream is a streaming documentary service with thousands of films about history, science, nature, travel, biography, etc. $20.00 a year, on the Web, or with an App.
Baronfig makes high quality notebooks, hardcover and soft, planners, desk pads, and great pens. I love the hardcover Confidant as well as teh soft-ver Vanguard. Three different kinds of ruling available, too.
Story Supply Co makes quality notebooks and supplies for writers. I particularly like their pocket-sized stapled notebooks.
I recommend two free email newsletters: Emerging Tech Brew and Morning Brew, a more general business/economy newsletter. Morning Brew and Emerging Tech Brew are well-written, interesting, and not over-the-top marketing drivel. I suggest trying Morning Brew first, which, by the way, might result in me getting some nifty stickers or even a coffee cup.