Three are definitively multiplayer focused (Super Smash Bros. Melee, Soul Calibur IV, Mario Kart DS)
One has both a strong single-player and multiplayer, and I wouldn't really say it's "focused," on either (Super Monkey Ball 2). I would say that without the multiplayer it probably wouldn't have made my top 10; both the single-player and multiplayer are superb, but if the game was just one of them I probably would have found it lacking in content.
Two have multiplayer modes that some people put a ton of time into but I never did (Pokemon Platinum, In the Groove 2). The former is sort of like Monkey Ball in that it has both a big single-player and multiplayer component, but I've never been hugely into competitive Pokemon or just battling with my friends. The latter is basically just the same game but with another person in MP and I've only played ITG2 by myself.
The others (Twilight Princess which may get usurped by Breath of the Wild as I play it more, Fire Emblem Fates, Virtue's Last Reward, Elite Beat Agents) are single-player focused.
So if I had to pick a number I'd say SMB2 is multiplayer focused and the other two I mentioned aren't, which would make four.