Hotkeys for selection cycling by hierarchy

There is a couple of very underrated hotkeys - select parent/child - "[" / "]". It could be very convenient and especially useful for complicated hierarchies/armatures, when it's almost impossible to select by clicking anymore. Unfortunately a couple more keys miss for it to be worth remembering for most: cycling through next/previous siblings in current hierarchy level.

That way you'll have a complete child/parent/next-previous sibling control system, which would make these hotkeys a universal tool. The matching hotkeys might be " ;" , " ' " under "[" , "]" .

Though personally I'd probably set them to main arrows as they're quite central for efficiency.