SeamlessCanvas is an online tool for creating, checking, and editing seamless patterns and textures. You can generate seamless repeat patterns, turn uploaded images into seamless tiles, preview pattern repeats, fill larger pattern areas, and create seamless textures for design, print-on-demand, wallpaper, fabric, packaging, and digital artwork.
It also includes useful image tools such as image compression, format conversion, color adjustment, and pattern checking to help designers and creators prepare repeatable artwork more easily.
Try it here: https://seamlesscanvas.com