What Glyphs are good for death knight tanking?

This will depend somewhat on your spec, of course. You’re generally going to want the Glyph that corresponds to the 36 point tanking talent you took (Bone Shield, Unbreakable Armor or Vampiric Blood). In order of importance, Bone Shield is mandatory if you’re Unholy. There is no question about it. Unbreakable Armor is slightly less so, and I’ve personally found that I rarely use UBA much unless I’m trying to give my healer(s) some breathing room. This on top of the recent change to UBA’s Glyph (Grants 15% additional armor instead of +5% Parry and removing Strength). Though the extra 10% Parry is mainly what I use it for, it’s definitely a buff, and I will be keeping it regardless. Vampiric Blood’s Glyph is also well worth taking for an extra 10 seconds to its duration.

Other Major glyphs that will be very helpful:
- Icy Touch. This Glyph is pretty much awesome. More Runic Power is a lot better than less Runic Power, especially when you have high enough avoidance that you can drop Rune Strikes with large regularity.
- Rune Strike. This is was buffed fairly well in 3.0.8, as the RP cost increase has been removed, and this makes it much more attractive than it used to be
- Obliterate. If you are Frost, Obliterate is your bread and butter, and I can almost guarantee you will want to have this Glyph. 20% more damage is the tasty gravy
- Death and Decay. Very good for many builds, but Unholy in particular. 20% more damage to an ability you use to generate a large amount of your threat.

Minor Glyphs you will want:
-Pestilence. This is mandatory. If you do not have this Glyph, get it right now. As one of the only Minor Glyphs that’s useful for any spec, let alone tanking, it’s an excellent investment.
-Horn of Winter. Quality of life Glyph, and there’s really nothing else anyway. Much better than it used to be, now that it increases the duration by 1 minute.

Unfortunately, with the exception of these Glyphs there’s really not much else worth considering. What few other Glyphs there are that aren’t abysmally bad are more useful in PvP or DPS roles. Frost Strike is better after 3.0.8, now that it reduces the RP cost, and for your third Major it will usually be a choice of Rune Strike or Frost Strike.