Alternatives to physics.ignorecollision() to ignore 2d collisions

Like I said in the title, is there any way to recreate the ignorecollision method for 2d objects without the use of layers? Layers are certainly the easiest solution, but since they're limited, it's not the optimal. Let's pretend that I got a bucket that will "catch" objects randomly falling down throught the scene, those objects need to collide with the bucket's "floor" but not with each others, how would you do this ? I didn't actually found anyway to make it, even with the use of isTrigger / collider.enabled properties.. any Idea ?