Depending, maybe a 2nd parry instead of hardy, remembering you can parry for friends. If you have magic items you are converting and can free up enough for intercept, there's also the "heroic intercept" ritual which can give you a resolute per ritual charge to use on things thrown at people nearby. (Intercept is 2 per and buyable per /10 vs /25 for resolute normally or /30 for parry - so its a way to relatively cheaply get some defenses for nearby friends.) This is assuming by tank you mean "take the hits so those near me don't".

If you mean tanky more as "can take a beating for a long time" consider buying some wear extra armor if you can phyrsep it. Its easier to physrep more armor in 2.0, and hitting mid-40's or 50's in armor is a solid tanking decision. And armor refitting is infinite, unlike healing. And if you end up with enough WEA, the "Armored Shell" enchantment might be useful as it'll give you your WEA ranks also as HP, so its sort of a way to double up on your investment and make mettle more usable.