With Dynamax Cannon buffing Max level Guard to Max+ level for everything except Zacian and Zamazenta, the guard user ranking is shaken up. The current understanding is that Max+ level shield gives 80 HP instead of 60 HP.
The updated rankings are below. 2 indicates that the fastest fast move takes 2 turns. Zamazenta-C4x indicates Zamazenta Crowned Shield's bulk when having 4 shields rather than 3. Unreleased gigantamax and datamined dynamax options are also included marked with parentheses. Additional ice resist options are given since Lapras is currently only available as Gigantamax.
- Normal: Shuckle2 > Zamazenta
- Fighting: Gengar
- Flying/Fairy: Metagross
- Poison/Rock/Bug/Steel: Zamazenta-C
- Ground: Articuno2 > Butterfree
- Ghost: Blissey
- Fire: (Coalossal)2 > Omastar
- Water: (Appletun)2 > Suicune2 > Latias
- Grass: Eternatus2 > Corviknight
- Electric: (Sandaconda) > (Appletun)2 > Latias
- Ice: Lapras > Zamazenta-C4x > Suicune2 > Zamazenta-C
- Psychic: (Malamar) > (Umbreon)2 > Metagross
- Dragon: Zacian-C
- Dark: Urshifu-S > Zamazenta-C4x > (Umbreon)2 > Zamazenta-C
Notable changes: Metagross now beats Zacian against Flying and Fairy type attacks. Corviknight and Urshifu Single Strike beats Zamazenta against Grass and Dark respectively even with 3 vs 4 shields.
For more comprehensive data as well as the ranking without dynamax cannon, see here: https://gist.github.com/Mygod/4caf6bae721a0d6b1d57615763e96c19
by MygodStudio