Although a quite pricey bound item, I've found the Horn of Urgok to be a fairly good investment as a magic item if you can find the points for it on anyone of your characters. It costs as much as a snotling unit and requires you to reach a casting value of 5 for the effect to go through. If it does, all friendly units on the battlefield will get a +1 bonus to their leadership while all enemy units will test on -1 until the end of the turn.
This might not seem like very much, but in 8th edition and in particular for Orcs & Goblins, leadership tests are so crucial. Most of our tactics depend on passing our steadfast breaktests and so increasing your Warboss' inspiring presence to leadership 10 really makes a difference. Not to mention that it's effectively an extra free point of combat resolution for all your troops as long as you're winning your combats.
Under normal circumstances, you should be getting at least one extra power dice from the winds of magic than your opponent. The optimal way to make use of the Horn is to throw only a single dice at it. 2/6 times it'll go through, which creates quite a dilemma for your opponent. If they throw only a single dice at it, it's the same 2/6 risk that the wizard will lose concentration, so if they want to really make sure to remain concentrated they will throw 2 dice at it, making it easier for you to get through the rest of your spells.
I've tried out the horn in my last couple of games and I've been pleased with it, although it does require you to have enough points left over on one of your characters. I usually give it to my Great Shaman, together with the Talisman of Preservation, Waaagh paint and Ironcurse Icon for a full point total. The 4+ ward save and T5 means he's quite safe against the downside of the Horn (on a roll of '1' takes a S5 hit).
Feel inspired enough to give it a try? Let me know how it goes!