[name]Samuel[/name] - [name]LOVE[/name] [name]Samuel[/name]. [name]Sam[/name] just makes me smile. I think it’s so timeless and I love its Biblical ties. It’s a great choice.
[name]Linus[/name] - [name]LOVE[/name] [name]Linus[/name], too. I’ve been thinking about it as a FN, and it’s currently a MN on my list ([name]Avery[/name] [name]Linus[/name] [name]Benjamin[/name]) but that combo could change in the near future.
[name]Elliott[/name] - love this name, too, and I’ve been considering it several places as a MN, but I vastly prefer the [name]Elliot[/name] spelling.
[name]August[/name] - love. Apparently I just love your whole list.
[name]Jack[/name] [name]August[/name] [name]Cole[/name] is my second favorite boys’ name, so this one is a bit more special to me. 
[name]Gabriel[/name] - love this, too.
I like the nn [name]Gabe[/name] a lot. It’s so handsome for a boy.
[name]Milo[/name] - I like this a lot. Much more than [name]Miles[/name], anyway! It’s so quirky and interesting. I don’t know why this is often used as a nn for [name]Miles[/name], since I can see this aging just as well (if not more!) than [name]Miles[/name] does. It’s perfect.
[name]Xavier[/name] - haha, I love @saracita00’s commentary for this. I say [name]Xavier[/name] this way, too. I like it in theory, but every time I see [name]Xavier[/name] in a combo, I sorta cringe. For some reason, I don’t really like it paired with anything–both as a FN or a MN! I know a mom who has an ADORABLE little boy named [name]Ethan[/name] [name]Xavier[/name], though, and I actually don’t mind that…
[name]Julien[/name] - Lots of times I love French variations, but in this case, I think it makes [name]Julian[/name] look more feminine. Lots of people find [name]Julian[/name] girly (I don’t), but changing it to [name]Julien[/name] feminizes it to me.
[name]Oliver[/name] - I like it. I used to not see its appeal, and I still much prefer [name]Olivia[/name] and [name]Olive[/name] on girls to [name]Oliver[/name] on a boy, but it’s handsome, and quirky. My only association to the name is [name]Oliver[/name] on the Canadian TV show Rookie [name]Blue[/name], and he is hilarious there. So I have a good association to it now.
[name]Hugo[/name] - I can see its appeal, but it seems perennially grown up. I like [name]Hugh[/name] better, but I prefer both as MNs.
[name]Samuel[/name], [name]Linus[/name], [name]Elliot[/name], and [name]August[/name] are my favorites!
Good luck!