I read in a different thread that in addition to MR, elemental resistance is crucial to dealing with Bosses.  I know there is some gear which helps with elemental resistance, but even if I equip the elemental resist equipment I am aware of, the most elemental resistance I can get is 90%.

Red Dragon Armor - 20%

Ring of Fire x 2 = 30% x 2 = 60%

Fire Cloak =  10%

Total = 90%

Am I missing some other items which provide elemental resistance?

https://l1justice.com/lineage/database/items/20181/

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+6dq ammy

And you can also make food. Floating eye meat makes +10 all ele resist. lesser dragon is +15mr, and +10 all ele resist.

Thank you . I hadn't even thought of using food for mr

also just adding the new feather stuff:

-ts gives +10all,

-and there is also an ammy that gives +10%

..after that its enchanting lv3 accessories