These work best if you plan your character from the start with Warding Bond in mind.
3 levels of Bear Totem can give you a rage that provides resistance to damage that is not psychic*.
Bard or Paladin
The spell Heroism, depending on your Charisma, can provide a significant amount of THP.
Wizard, Vampiric Touch spell
5 levels give you constant healing opportunity, especially if you have Life Domain.
Wizard, Arcane Ward
2 levels give you magical protection, that is even rechargeable with cleric spells.
If you do not mind changing often.
Heavy Armor Master
Only works if the damage type is carried over*, and only against weapons even then.
Heroism once per day.
Ring of Spell Storing
Let the Barbarian or Moon Druid cast one Warding Bond on you.
Let the Bard or Paladin cast Heroism on you.
*You have to decide with your DM what type of damage Warding Bond is. Either it carries over the original damage type, or is untyped. So if the warded creature takes fire damage, the damage you take is either fire, or not.