I like short names or names with unique nicknames that have similar styles.
my lists are:
Boys:
[name_u]August[/name_u] ‘Gus’
[name_m]Wells[/name_m]
[name_m]Harris[/name_m]
[name_m]Ian[/name_m]
[name_u]Reid[/name_u]
[name_u]Levi[/name_u]
Girls:
[name_m]Ivy[/name_m]
(I have a hard time coming up with girl names, I prefer girl names that don’t end in ‘a’)
[name_f]My[/name_f] question is, what boy names on my list (or other suggestions) match best with [name_m]Ivy[/name_m]?
You have a lovely selection of names!
Looking at your list my two favourites as a sibling for Ivy are Wells & Reid.
Wells is a lovely name handsome, outdoorsy, literacy choice that feels so attractive teamed with Ivy. Ivy & Wells are incredibly attractive together whimsical and ethereal with a sweet nature tie.
Reid feels bookish, smart and well tailored. I love Reid with Ivy they both just feel so well polished, have strong vintage vibes and look so attractive together.
Some other ideas could be Simon, Rhett & Jude.
Hope this helps
[name_m]Ivy[/name_m] is so sweet! I like it paired best with [name_u]August[/name_u] (Gus). More suggestions are…
Boys:
[name_u]Hendrix[/name_u] (Hank)
[name_u]Axel[/name_u]
[name_u]Flynn[/name_u]
Girls:
[name_u]Macey[/name_u]
[name_f]Alison[/name_f]
[name_f]Violet[/name_f]
From your list I would pair [name_m]Ivy[/name_m] with [name_u]August[/name_u] (Gus).
Suggestions:
[name_u]Rowan[/name_u]
[name_m]Nathaniel[/name_m] “Nate / Thane”
[name_u]Arthur[/name_u]
[name_u]Rhys[/name_u]
[name_m]Knox[/name_m]
[name_m]Lachlan[/name_m] “Lach / Lachy”
[name_m]Sebastian[/name_m] “Seb / Baz”
Of your suggestions I like:
[name_m]Ivy[/name_m] and [name_u]Gus[/name_u]
[name_m]Ivy[/name_m] and [name_u]Reid[/name_u]
Other suggestions
Boys:
[name_u]Ellis[/name_u]
[name_u]Cove[/name_u]
[name_u]Fox[/name_u]
[name_m]Moss[/name_m]
[name_u]James[/name_u]
[name_u]Arlo[/name_u]
[name_m]Ned[/name_m]
[name_u]George[/name_u]
Fred/Freddie
[name_u]Lisle[/name_u]
[name_u]Flynn[/name_u]
[name_u]Owen[/name_u]
[name_u]Evan[/name_u]
Girls:
[name_u]Fern[/name_u]
[name_f]Grace[/name_f]
[name_f]Nell[/name_f]
[name_u]Skye[/name_u]
[name_u]Ocean[/name_u]
[name_f]Elle[/name_f]
[name_f]Alice[/name_f]
[name_u]Alix[/name_u]
[name_f]Enid[/name_f]
[name_f]Edie[/name_f]
[name_f]Amy[/name_f]
[name_f]Chloe[/name_f]
[name_u]Cleo[/name_u]
[name_u]Evelyn[/name_u]
[name_u]Erin[/name_u]
I love the outdoorsy and whimsical vibes!
[name_m]Ivy[/name_m] and Wells… hmm what would be a good match for a third?
From your list I probably like [name_u]August[/name_u] the best with [name_m]Ivy[/name_m]. Maybe outside of that I like [name_u]Everett[/name_u].
[name_u]Gus[/name_u] and [name_m]Ivy[/name_m] though is so sweet
With [name_m]Ivy[/name_m], [name_u]Reid[/name_u], [name_m]Wells[/name_m] and [name_u]August[/name_u] are wonderful!!
A few other ideas with [name_m]Ivy[/name_m]:
[name_u]Finn[/name_u], [name_u]Jude[/name_u], [name_m]Silas[/name_m], [name_u]Jett[/name_u], [name_u]Fen[/name_u], [name_u]Flynn[/name_u], [name_u]Jasper[/name_u], [name_m]Caspian[/name_m], [name_m]Roman[/name_m]
[name_f]Lucy[/name_f], [name_f]Belle[/name_f], [name_u]Cleo[/name_u], [name_f]Edith[/name_f], [name_f]Neve[/name_f], [name_f]Alice[/name_f], [name_u]Florence[/name_u], [name_f]Carys[/name_f]
Great list! I personally love [name_m]Ivy[/name_m] paired with [name_m]Wells[/name_m] or [name_u]Gus[/name_u] best just based on how they sound together, but none of the others would be bad options either, so you really can’t go wrong!
Some suggestions I have for your consideration……
Girls:
[name_u]Florence[/name_u] nn [name_f]Flo[/name_f], [name_u]Floy[/name_u], or Flory/Florrie
[name_f]Beatrice[/name_f] nn Bea/Bee
[name_f]Margaret[/name_f] nn [name_f]Maggie[/name_f]
[name_f]Winifred[/name_f] nn [name_f]Winnie[/name_f], [name_u]Win[/name_u], or [name_u]Freddie[/name_u]
[name_u]Evelyn[/name_u] nn [name_f]Evie[/name_f]
[name_u]Vivian[/name_u] nn [name_f]Viv[/name_f], [name_f]Vivi[/name_f], or [name_m]Ian[/name_m]
[name_f]Felicity[/name_f] nn [name_f]Effie[/name_f], [name_f]Flick[/name_f], [name_f]Lettie[/name_f], [name_f]Fia[/name_f], Cece/Cici, [name_f]Flossie[/name_f], Issie/Izzy…… there’s so many lovely nickname possibilities, making this one of my favorite suggestions if you’re planning on calling her by something other than what’s on the birth certificate
[name_f]Evangeline[/name_f] nn [name_f]Evie[/name_f], [name_f]Eve[/name_f], [name_f]Eva[/name_f], [name_f]Gigi[/name_f], or [name_f]Lina[/name_f]
[name_f]Gwendolen[/name_f] nn [name_f]Gwen[/name_f] or [name_u]Lennie[/name_u]
[name_f]Charlotte[/name_f] nn Charlie/Charley/Charlee or Lottie/Lotte
[name_f]Phoebe[/name_f] nn [name_f]Bebe[/name_f]
[name_f]Violet[/name_f]
[name_f]Olive[/name_f]
[name_u]Hazel[/name_u]
[name_f]Mabel[/name_f]
[name_u]Fern[/name_u]
May/Mae
[name_f]Scarlett[/name_f]
[name_f]Nellie[/name_f]
[name_f]Maud[/name_f]
Boys:
[name_m]Frederick[/name_m]
[name_m]Theodore[/name_m]
[name_u]Jameson[/name_u] (aside from the obvious nickname of [name_u]James[/name_u], there’s also [name_u]Jay[/name_u], [name_u]Jem[/name_u], and Amos)
[name_u]George[/name_u]
[name_u]Leo[/name_u]
[name_u]Jack[/name_u]
[name_m]Oscar[/name_m]
[name_m]Felix[/name_m]
Unisex:
[name_u]Sage[/name_u]
[name_u]Finn[/name_u]
[name_u]Rowan[/name_u]
[name_u]River[/name_u]
[name_u]Aspen[/name_u]
[name_u]Ash[/name_u]
[name_u]Quinn[/name_u]
[name_u]Parker[/name_u]
[name_u]Reese[/name_u]
[name_u]Jude[/name_u]
[name_f]Alice[/name_f]
[name_f]Maisy[/name_f] or [name_f]Maisie[/name_f]
[name_f]Amelia[/name_f]
[name_u]Evelyn[/name_u]
[name_f]Stella[/name_f]
[name_f]Evangeline[/name_f]
[name_f]Violet[/name_f]
[name_f]Daisy[/name_f]
[name_f]Grace[/name_f] or [name_f]Gracie[/name_f]
[name_f]Lucy[/name_f]
[name_f]Poppy[/name_f]
[name_f]Lily[/name_f]
[name_f]Mabel[/name_f]
[name_f]Pippa[/name_f]
[name_f]Betty[/name_f]
[name_f]Freya[/name_f]
[name_f]Dorothy[/name_f]
[name_f]Dot[/name_f]
I think [name_m]Ivy[/name_m] and [name_m]Wells[/name_m] are amazing together! And [name_m]Ivy[/name_m] and [name_u]Levi[/name_u] are so much fun together, with the shared sounds in a different order. [name_u]August[/name_u] and [name_m]Ivy[/name_m] are on my list though, so have to shout out that set as well 
[name_u]Wilder[/name_u] - [name_u]Wylie[/name_u]
[name_u]Hudson[/name_u] - [name_m]Hud[/name_m], [name_u]Sonny[/name_u]
[name_u]Sawyer[/name_u]
[name_m]Graham[/name_m]
[name_u]Carter[/name_u]
[name_u]Beckett[/name_u] - [name_u]Beck[/name_u], [name_u]Kit[/name_u]
[name_u]Wyatt[/name_u]
[name_u]Elliot[/name_u] - [name_u]Eli[/name_u]
[name_u]Rhett[/name_u]
[name_u]Lyric[/name_u]
[name_f]Astrid[/name_f]
[name_u]Collins[/name_u]
[name_u]Sutton[/name_u]
[name_u]Sloane[/name_u]
[name_f]Maeve[/name_f]
[name_u]Hazel[/name_u]
[name_f]Faye[/name_f]
[name_f]Daphne[/name_f]
I love the idea of [name_u]Cove[/name_u] 
[name_m]Ivy[/name_m], [name_m]Wells[/name_m] & [name_u]Cove[/name_u] for another brother!
I think for a sister I like the idea of [name_f]Flora[/name_f]! I think [name_m]Ivy[/name_m], [name_m]Wells[/name_m] & [name_f]Flora[/name_f] would be gorgeous.
From your boys’ list I love [name_u]Reid[/name_u] and [name_u]Levi[/name_u] with [name_m]Ivy[/name_m]
Suggestions for Girls:
[name_f]Alice[/name_f]
[name_f]Phoebe[/name_f]
[name_f]Daphne[/name_f]
[name_f]Blythe[/name_f]
[name_f]Iris[/name_f]
[name_f]Liesl[/name_f]
[name_f]Audrey[/name_f]
[name_f]Coralie[/name_f]
[name_f]Gwyneth[/name_f]
[name_f]Claire[/name_f]
[name_u]Hazel[/name_u]
[name_f]Eloise[/name_f]
[name_u]Ruby[/name_u]
[name_u]Piper[/name_u]
[name_f]Juliet[/name_f]
[name_f]Elowen[/name_f]
“-a” ending names I love and needed to toss in the contender ring - [name_f]Clara[/name_f], [name_f]Lydia[/name_f], [name_f]Stella[/name_f] and [name_f]Nora[/name_f].
N.B
Noticed a [name_f]Lucy[/name_f] suggestion and thought I should mention if you are not into the Batman franchise I’d suggest steering clear of
[name_u]Ivy[/name_u] and….
[name_u]Clare[/name_u]
[name_f]Liv[/name_f]
[name_u]Alix[/name_u]
[name_f]Chloe[/name_f]
[name_u]Lior[/name_u]
[name_u]Rumi[/name_u]
[name_u]Sloane[/name_u]
[name_u]Quinn[/name_u]
[name_f]Tamar[/name_f]
[name_f]Vera[/name_f]
Flier
[name_f]Tess[/name_f]
[name_f]Nell[/name_f]
[name_f]Eva[/name_f]
[name_f]Ada[/name_f]
[name_u]Lyric[/name_u]
Oh I love the name [name_f]Liesl[/name_f]!
[name_u]Love[/name_u] the nickname Liesi for [name_f]Liesl[/name_f]
[name_u]Ivy[/name_u] and Liesi or Lisi. LEEZ ee
[name_u]Or[/name_u] another idea is [name_u]Ivy[/name_u] and [name_f]Elise[/name_f], nicknamed Lisi. LEEZ- ee
I like the way the two vowel names sound together.