My cousin has two boys named Jayden and Aidan. Not sure what she was thinking...
I also know someone named Drea, and her siblings names are Conrad and Koltyn (girl). Very mismatched in my opinion.
Two boys: Hunter and Tanner. Really. I wonder what the next will be. Trapper? Cobbler? Whaler? Builder? Tracker?
I think the most jarring sibset that I can think of is Lynn and Penelope. Penelope (called Penny as she hated Penelope) was in my class at school and her sister was a few years above. They are completely different in length, style and origin.
Twins in my family called Leo and Cleo (both boys).
I also know a family with a Morgan, Taylor, Adrien, Corey, Charlie, and Stevie - they're all girls. At least the names match.
(siblings) Raven (b) and Annabel - that's kind of cool.
(twins)Jesslyn and Jazzlyn.
(siblings) Jett Philipus & Galaxy Philadelphia Elizabeth (g)
And siblings Briar Freeborn (b) & Hannah Jean. They're not bad names, but REALLY don't match.