Scimitar of Flames (Patreon)

Weapon (scimitar), rare

This magic weapon deals an extra 1d6 fire damage to any target it hits. While holding it, you can use a bonus action to speak its command word to cast the flame blade spell from it. This version of the spell uses the same attack bonus and ability modifier you use for the scimitar of flames; the spell ends early if you're no longer holding the scimitar. While holding only the scimitar and the blade created by the flame blade spell, you can attack with the flame blade using a bonus action after taking the Attack action with the scimitar.

See how the flames dance and move. Stay on guard, though, lest you get burned.