Silas x Azura/Orochi, Saizo x Felicia, Corin x Selkie/Azura/Hana, etc.
Support conversations that I've seen in Fates so far have been lackluster in general compared to Awakening (Oboro has been the saving grace). Lot of convos are better suited to be just talks between friends, not the types that would lead them to marriage.
And Silas seems like a dick in a lot of supports. He's too quick to judge people and always ends up apologizing. I hate that kind of shallow personality. I liked his support with Rinkah though.