I head to Horie each week for a class I have there on Monday nights. I've started taking detours weekly to visit Gallery Hokk, which I prefer to most other galleries because they feature a lot of Illustrators. It's run by Kyoda Creation, a creative group in the same building.
I originally went there to see "Maido Ookini!" A Kansai Dialect, 100 Person Exhibition, Part 2 • まいどおおきに！関西弁１００人展 ２, which was GREAT. I was actually being quite rude I though, snickering at most of the pictures. But I couldn't help it! There was some really funny stuff in there, like a bunch of blue aliens that watched you as you walked past, rabbits selling takoyaki and a kid pulling a cart with all Osaka's main attractions in it. I really need to catch up on my Kansai ben • 関西弁, because the exhibition made me realize I don't know half as much as I should; I had trouble understanding lots of it.
Keep an eye on Gallery Hokk, it's usually exhibiting some pretty cool Illustrators. If you head there in the evenings or on the weekends, you'll probably find the creators present, and quite happy to talk about what they're doing.
Gallery Hokk is perfect if you're wondering around Yotsubashi and the Horie area.