Following on from my girls list, here is a selection of names that were used 50 times or fewer for boys in 2017.
Adriel
Alaric
Alvin
Ambrose
Amos
Anton
Apollo
Aramis
Arnold
Aubrey
August/Augustus
Balthazar
Barnabas
Barry
Bartholomew
Basil
Baxter
Beck
Bellamy
Benji
Bernard
Bert/Burt
Bertram
Bertrand
Bill
Blaine
Bodie/Bohdi
Boris
Boyd
Brady
Bram
Brendan
Brett
Brixton
Bryson
Buster
Caesar
Cal
Carl
Cary
Cassidy
Cedar
Che
Cecil
Cedric
Chad
Clarence
Claude
Clement
Clifford
Clive
Clyde
Conan
Conrad
Constantine
Cormac
Cornelius
Cosmo
Craig
Crispin
Cyril
Dakota
Dale
Damon
Dane
Darnell
Darragh/Dara
Darren
Daryl
Darwin
Dashiell
Denver
Denzel
Derek
Desmond
Diesel
Digby
Donald
Donnie/Donny
Dougal
Duncan
Dustin
Dwanye
Earl
Eben/Ebenezer
Edgar
Eddison
Edmund
Elvis
Elwood
Emrys
Enoch
Ephraim
Errol
Etienne
Eugene
Evander
Everett
Ferdinand
Fintan
Finnian
Florian
Floyd
Forrest
Gage
Gareth (it'll be interesting to see if this gets more popular next year due to Gareth Souhgate)
Gavin
Gerald
Gilbert
Giles
Glen/Glenn
Godfrey
Godwin
Graham/Graeme
Grant
Griffin
Gus
Hal
Harold
Herbie
Heston
Horatio
Howard
Huey
Iago
Ignatius
Indigo
Ira
Ivo
Ivor
Jacoby
Jamil/Jameel
Jarvis
Jedidiah
Jeffery/Geoffrey
Jermaine
Jerome
Jerry/Gerry
Jethro
Joachim
Jolyon
Jonty
Judd
Jules
Julius
Justice
Keith
Kenneth
Kester
Kurt
Lemar/Lamar
Lance
Leander
Leland
Lemuel
Leopold
Lewin
Lex
Linus
Lionel
Lloyd
Luther
Lysander
Mac
Malcolm
Marius
Marlon
Marvin
Maurice/Morris
Melvin
Memphis
Merlin
Mickey
Mordecai
Neil
Nelson
Nigel
Nikita
Onyx
Oren
Oswald
Oswin
Paris
Peregrine
Phineas
Pierce
Pierre
Pip
Prosper
Ptolemy
Quentin
Quincy
Ranulph
Ricardo
Rocky
Rodney
Roland
Rollo
Ross
Roy
Rudolf
Russell
Ryker
Sacha
Saul
Seamus
Shiloh
Silas
Sol
Soren
Spike
Sterling
Stuart/Stewart
Sully
Tanner
Terence
Thaddeus
Timmy
Tobin
Todd
Trent
Trevor
Tyrell
Tyrone
Tyson
Valentino
Vince
Vlad
Wade
Wallace
Warwick
Wayne
Wilfred
Willis
Willoughby
Wolf
Wolfgang
Woodrow
Wren
Zeke
Zephyr
Zico
Zoltan
Stats can be found here