Respondents: 130 (This poll is closed)
I love your list @ladyhope, we have similar taste by the look of things, so it was so hard to choose just one! I went with [name_m]Sebastian[/name_m], because it is my son’s name and I absolutely adore it, but I also love [name_m]Julian[/name_m] (my top choice if I have a s find son), [name_m]Lucian[/name_m], [name_m]Gabriel[/name_m] and [name_m]Nathaniel[/name_m]. I think any of them would be wonderful with [name_m]Theodore[/name_m].
I love a lot of these - it was hard to choose! I settled on [name_m]Abel[/name_m], but [name_u]Elliott[/name_u], [name_m]Lucian[/name_m], and [name_m]Julian[/name_m] were not far behind.
I chose [name_m]Sebastian[/name_m] because I think it goes wonderfully with [name_m]Theodore[/name_m]. [name_u]Theo[/name_u] and [name_m]Bas[/name_m] sounds cute. (Its also on my short list).
[name_m]Sebastian[/name_m] is top pick then [name_u]Elliott[/name_u] and then [name_m]Julian[/name_m]
[name_m]Theodore[/name_m] is gorgeous & so are the names of your fur babies, I especially like [name_f]Sylvie[/name_f] & [name_f]Delphine[/name_f], Lol! Anyway, [name_m]Lucian[/name_m] is definitely my favorite followed by [name_m]Sebastian[/name_m] & then [name_m]Gabriel[/name_m].
We know a [name_m]Lucien[/name_m] and they nickname him “[name_u]Lucky[/name_u]”. It’s very cute, my only reservation is that it makes me think of [name_m]Lucius[/name_m] Malfoy from the [name_m]Harry[/name_m] [name_m]Potter[/name_m] books.
I picked [name_m]Julian[/name_m]. I have a [name_m]Julian[/name_m] and I love his name. He gets both [name_m]Julian[/name_m] and [name_u]Jules[/name_u], although he prefers his whole name.
[name_m]Nate[/name_m] and [name_u]Theo[/name_u] seem like a great sib set. And [name_m]Nathaniel[/name_m] and [name_m]Theodore[/name_m] go equally well together!
Thanks so much everyone!! Keep them coming, please 
I think [name_m]Ezekiel[/name_m] is being seriously overlooked! [name_f]Lovely[/name_f] sounds and a lovely nicknames, and criminally underused! Matches [name_m]Theodore[/name_m] really well in weight and length, and [name_u]Theo[/name_u] and [name_m]Zeke[/name_m] are really cute together
I love:
[name_u]Elliot[/name_u]
[name_m]Ezekiel[/name_m]
[name_m]Malcom[/name_m]
[name_m]Julian[/name_m]
[name_m]Nathaniel[/name_m]
[name_m]John[/name_m]
I voted [name_m]Abel[/name_m] - absolutely adore this name and it goes so beautifully with [name_u]Theo[/name_u]. I also love [name_u]Elliot[/name_u] and [name_m]Sebastian[/name_m] too. I hope you fall in love with of them, you’ve got some fabulous names on your list! 
I love so many of these! I think [name_m]Gabriel[/name_m], [name_m]Nathaniel[/name_m], [name_m]Sebastian[/name_m], [name_m]Lucian[/name_m] and [name_m]Julian[/name_m] are especially perfect with [name_m]Theodore[/name_m].
I voted for [name_m]Nathaniel[/name_m] (my personal favourite) but, on second thought, they are probably a bit close and the meaning is identical.
I’ll re-vote for… [name_m]Lucian[/name_m]! Beautiful, underused, and [name_m]Louie[/name_m] is a gorgeous nickname.
I voted for [name_m]Nathaniel[/name_m]. [name_m]Ezekiel[/name_m] and [name_m]Nathaniel[/name_m] are my favorites because they are strong names with great meanings and friendly nicknames. They are similar to [name_m]Theodore[/name_m], but each special in their own way.
I love [name_u]Elliott[/name_u], [name_m]Lucian[/name_m], [name_m]Julian[/name_m], [name_m]Nathaniel[/name_m], & [name_m]Sebastian[/name_m]. I chose [name_u]Elliott[/name_u], but all of the ones I just listed would go great with [name_m]Theodore[/name_m] as well. I’m not too crazy about your other options personally or with [name_m]Theodore[/name_m].
It was too hard to choose just one!
With [name_u]Theo[/name_u], I like:
[name_m]Ezekiel[/name_m] “[name_m]Zeke[/name_m]”
[name_m]Malcolm[/name_m] “[name_m]Mac[/name_m]”
[name_m]John[/name_m]
[name_m]Gabriel[/name_m] “[name_m]Gabe[/name_m]”
I had a hard time deciding as there are so many great choices! I wanted tyo vote for [name_m]Ezekiel[/name_m] as [name_u]Theo[/name_u] and [name_m]Zeke[/name_m] are wonderful together. My only pause was that it might be tough to call “[name_u]Theo[/name_u], [name_m]Ezekiel[/name_m]!” Then again, [name_u]Theo[/name_u] is a nn and you likely would use [name_m]Zeke[/name_m] with [name_u]Theo[/name_u].
I voted for [name_m]Sebastian[/name_m] as that is adorable, too. I would consider [name_m]Zeb[/name_m] as the nn. It has a stronger presence like [name_u]Theo[/name_u] and [name_m]Zeke[/name_m]. Or maybe [name_m]Baz[/name_m]. ([name_m]Basil[/name_m] just came to mind. [name_m]Theodore[/name_m] and [name_m]Basil[/name_m]. [name_u]Theo[/name_u] and [name_m]Baz[/name_m].)
I voted for [name_m]Malcolm[/name_m] ‘[name_m]Mac[/name_m]’ as this is a strong and classic choice that is underused and unexpected, and I love [name_u]Theo[/name_u] and [name_m]Mac[/name_m] together. I also like [name_m]Sebastian[/name_m], [name_m]Nathaniel[/name_m] (or is it too close to [name_m]Theodore[/name_m]?) [name_u]Theo[/name_u] and [name_m]Nate[/name_m] are good though. I also like [name_m]John[/name_m].
I love your entire list! Looks like you’ve settled on some great names all around, but ultimately I voted for [name_m]Malcolm[/name_m], since it’s a solid, slightly under appreciated classic! I was excited to see it on your list! [name_m]Gabriel[/name_m] and [name_u]Elliott[/name_u] are probably my next two picks.
[name_u]Elliott[/name_u], [name_m]Abel[/name_m], [name_m]Nathaniel[/name_m], and [name_m]Julian[/name_m] are my top picks for you! I voted for [name_u]Elliott[/name_u] because it is what I’m planning on naming my next boy. I also love [name_m]Abel[/name_m] as I’m using this for my son’s middle name who is due in 10 days!