The best are Jobo sheet film clips, which punch one tiny hole in the rebate, but they hold any size sheet securely and perpendicular to the drying line, so you can fit a lot of sheets in a small space. They're absurdly expensive
Alternately, use clothespins, but turn the two sides of the pin around so that instead of clipping at the usual end they clip at the handle end, reducing contact area with the film--an Ansel Adams trick.
A few people seem to get along with the Yankee tank, but most people have problems with them, due to the odd side-to-side agitation method that seems to be the only practical method, unless you have a few of them and use them kind of like tanks and hangers. I don't recommend trying the Yankee rack in a normal deep tank designed for hangers, because the rack floats. I'd sooner recommend learning to develop in trays, and then you'll be able to handle any odd format that comes along.