Magic items do not require attunement.
All classes can use rings, potions, magical armor (with respect to their class limitations), jeweler, etc.
Who Can Use Scrolls?
Only wizards and clerics can read scrolls.
Those without spellcasting ability (i.e fighter, thieves) cannot activate a scroll's power.
Who Can Use Wands?
Wands hold stored spells that respond to will and training.
Only Wizards can use any wand.
Who Can Use Staves?
A staff acts as an extension of a caster's will.
Only wizards and clerics may unlock any magical or spell casting staves.
Who Can Use Rods?
Rods are relics of great potency.
Only wizards and clerics can command them.