I like your naming style! It’s similar to mine 
[name]Adrian[/name] -Like, but I have a 15-year-old friend named [name]Adrienne[/name], so I can really only see it on a girl. [name]Don[/name]'t let that stop you though!
[name]Allen[/name] -[name]LOVE[/name]. I think it’s such a classic, classy name! And [name]Lenny[/name] is such a cute nn
[name]Alexander[/name] -Like, but [name]WAY[/name] popular. At the summer camp I worked at, I knew 5 [name]Alex[/name]'s over 12, and NINE under 12. 2 were girls.
[name]Ambrose[/name] -Nice! A little bit much, but nice.
[name]Andrew[/name] -One of my personal faves, love then nn’s [name]Andy[/name] and [name]Drew[/name].
[name]Anthony[/name] -also VERY popular right now, I can name you 4 from my HS off the top of my head and I had 2 campers named [name]Anthony[/name].
[name]Archer[/name] -I named one of my characters [name]Archer[/name]! It’s hard to live up to, though, I think.
[name]August[/name] -I think this is very… not hipster, but underground maybe. It’s a name people will think is cool. (Because it is!)
[name]Benjamin[/name] -So classic, so cool. Keep it. I know very few Benjamins.
[name]Blake[/name] (DH loves, I think of [name]Blake[/name] Lively) -I think it’s nice, but feminized.
[name]Briar[/name]/[name]Brier[/name] -[name]LOVE[/name] this for a boy. Seriously.
[name]Broderick[/name] -Makes me think of [name]Matthew[/name] [name]Broderick[/name]. If you like that, go for it.
[name]Bryce[/name] -For some reason, this feels kinda dated to me.
[name]Carson[/name] (Again, dh loves, isn’t this becoming a name used for girls?) -I think this name is one of those kinda unisex, rather popular names. Avoid if you don’t want ultra-popular. I had a 6 year old [name]Carson[/name] at camp, but he was a boy. [name]Don[/name]'t know what that says.
[name]Charles[/name] -So classic! My cousin is named [name]Charles[/name] (nn [name]Charlie[/name]), so I’m biased.
[name]Colin[/name] -I have loved this name since I was 6! It’s such a classy name, IMHO.
[name]Damian[/name] -The only [name]Damian[/name] I know is a troublemaker who swears constantly, so I dislike it, but I do admit it’s a good solid name.
[name]Declan[/name] -Solid Irish name, gaining in popularity though.
[name]Dexter[/name] -It’s losing it’s [name]Dexter[/name]'s Lab nerd rep, but slowly.
[name]Dominic[/name] -[name]ADORE[/name] this! I had a great [name]Dominic[/name], he went by [name]Nicky[/name].
[name]Finn[/name] (DH adores this, but isn’t it getting super trendy?) -VERY trendy right now, but so handsome!
[name]Gavin[/name] -On my personal favorites list. It’ll sound good next to his classmates, but stand out!
[name]Ian[/name] -I know maybe 3, all over 12. It’s a good name, a little boring compared to some of your others though.
[name]Jackson[/name] -This name bothers me for some reason. I also had a [name]Jackson[/name] as a camper. Troublesome and headstrong, but cute.
[name]James[/name] -GREAT name, definitely popular right now. There are two boys named [name]James[/name] on my street, both under 7!
[name]Joseph[/name] -Solid bibilical name, definitely dated to me. But then my uncle’s name is [name]Joseph[/name].
[name]Jude[/name] -[name]LOVE[/name] [name]LOVE[/name] [name]LOVE[/name].
[name]Keelan[/name] -Feels feminine. Too similar to [name]Keeley[/name]/[name]Kelsey[/name] for my taste. Also feels kinda made up.
[name]Keiran[/name] -I have to admit, I prefer the [name]Kieran[/name] spelling. By that’s my little bro’s name, so maybe I’m biased? 
It’s a handsome, uncommon name.
[name]Leland[/name] -Cool! Not as good as some of your others though.
[name]Leo[/name] -Feels a little insubstantial to me, but if you dislike the full names it would work. Maybe as a middle?
[name]Nathan/name -[name]Nathan[/name] is a great, underused name, IMHO!
[name]Nolan[/name] -I don’t like [name]Nolan[/name]. [name]Don[/name]'t know why.
[name]Owen[/name] -I like this!
[name]Preston[/name] -[name]Just[/name] makes me think of [name]Elvis[/name] [name]Presley[/name]. Or a starbaby. [edit: [name]Kelly[/name] [name]Preston[/name] AND [name]Sean[/name] [name]Preston[/name] Spears count against it.]
[name]Rhys[/name] -Pronounced [name]Reece[/name]? I like it, but the majority of people I know couldn’t pronounce that and would call him [name]Rice[/name] or Riss.
[name]Spencer[/name] -Strong name, I think it would work well for a baby or a man.
[name]Trevor[/name] -[name]Adore[/name]!!
[name]William[/name] -Strong, solid, and not quite as popular as one would think! I love the nn [name]Will[/name].
My favorites from your list:
[name]Allen[/name]
[name]Andrew[/name]*
[name]Benjamin[/name]
[name]Briar[/name]
[name]Colin[/name]*
[name]Dominic[/name]
[name]Gavin[/name]
[name]Jude[/name]
[name]Kieran[/name]
[name]Spencer[/name]
[name]Trevor[/name]*
Good luck!