My 5 favourite white cards are probably these, in no particular order:
Always Watching - A relatively low-cost enchantment that gives a poop-tonne of versatility to most creature-based decks. Maybe more so now, with the advent of exert mechanics. The +1/+1 is just gravy on the cake! In the past, I have made the mistake of forgetting it doesn't benefit tokens, though.
Knight of the White Orchid - A 2/2 first-striking ramp creature for
that's a lot of value for a little cost. In a predominately white deck, he's a great, multi-purpose tool.Declaration in Stone - In short supply, 2 mana to exile one or more creatures? Yes, please. Especially, if your opponent goes wide with tokens, this little expenditure can change the playing field. And how many times have you slapped down Ulamog with a smugly confident grin on your face, only to have it wiped off with the deft tapping of two plains? It's happened to me, that's for sure.
Sram's Expertise - Four mana nets you three bodies, and casts another, lower-cost spell for free. This kind of versatility, I like. It's especially fun if you manage to chain Expertise spells-- Rishkar's>Sram's>Karl Zev's.
Hanweir Militia Captain/Westvale Cult Leader - Maybe not the most powerful card on its own, I love the implied story behind this card. Like many SOI cards, there was a sense of rationale behind the mechanic, and it was well-reflected in the art. This one is more of a feels-good choice, rather than a play-mechanic choice.
Sorry for derailing your post, HinterlandSage.
