Scavenge barrage (the one you don't have) is alarmingly good if you can stomach going light on shrecks and floating muni to make it better.
Offmap LeiG barrage for OST is the best offmap in the game for wiping weapon teams, and their weapons. It's the more expensive, better pathfinder artillery.
Every stuka ability is great, but not really 'artillery'. But the stuka incendiary bombs are the equivalent of incendiary arty.
Zeroing artillery is absolutely amazing if your opponent has a snared heavy tank or just a big blob. Sadly, IIRC, it's buggy right now.
EDIT: Oh, and Sector artillery? Do it. I don't know why people stopped using this since the beta, even, seeing as it never got a nerf. Maybe because it never comes with tigers. But on maps with large sectors (Admittedly, usually 4v4 land), it's a beauty