Here, the bluejays are agressive enough that everything else flies off whenever they land.
The grackles are agressive as well, but fortunately, there are not many of them here.
I have four feeders at a time, plus two suet feeders. I put a safflower seed feeder up for the cardinals and house finches, a hopper-style feeder with wild finch food that the painted buntings, house finches, goldfinches (while they are here), and cardinals will feed out of. a wire cage feeder with whole sunflower seeds in the shell for titmice and chickadees, and a platform feeder with cracked corn and whole sunflower seeds for anyone who likes them.
I use four suet feeders, and have red-bellied woodies, downie woodies, and ladder-back woodies, plus the cardinals have discovered that they love home-made suet- they probably eat as much of it as the woodpeckers do.
I take the finch feeders down once they migrate north and put them back up when they return after breeding season.
Do you have hummingbirds up there?