DynamicPunch is another fun one to mess with, especially now that there's a Gravity tutor in HG/SS which is widely available, but sadly I think that tutor is also once per save file. I'm not positive, since I never used mine, but since it's a random NPC that teaches it to you and not available at the Battle Frontier I'm assuming it to be so. Body Slam and Counter are always good ideas, especially Body Slam for bulky sorts of things. Seismic Toss has a few applications (Kecleon, Mawile, Sableye, Dusclops, Chansey/Blissey, Wigglytuff, etc.). Double-Edge is also good for a lot of things but, as you said, that ship has sailed. Most other tutors off the top of my head either suck or are already TMs/Tutors available in 4th gen.