I think [name_m]Todd[/name_m] could work as a nickname for [name_m]Theodore[/name_m] (although it might be a struggle to have that used over the more popular [name_m]Theo[/name_m] and Teddy). A major stretch but maybe something like [name_m]Aristotle[/name_m] because the ‘tot’ sound is kinda like [name_m]Todd[/name_m]?
[name_m]Other[/name_m] ideas but again all a bit of a stretch: Torndon, Torid, [name_m]Thaddeus[/name_m]
Maybe a combo like: [name_m]Tobias[/name_m] [name_m]Rodney[/name_m], [name_m]Thomas[/name_m] [name_m]David[/name_m], [name_m]Theodore[/name_m] [name_m]Douglas[/name_m], etc
Some more direct/obvious options: Toddney, Toddwell, [name_m]Todderick[/name_m], Todross / Todros / Todres