Soulbound
Soulbound runes are runes conjured by free account players which are soulbound to their accounts. That being the case, only characters on that specific account can use those runes. This restriction does not apply to runes created by premium accounts as those will not be soulbound.
Those kinds of runes are marked with an ankh and they cannot be used by any other player besides the one who conjured them in the first place, so please have that in mind. In order to spot those runes, as they are no different from normal runes, an option within game client Settings => Game of "Display markings around unique items" needs to be enabled which will show markings around a soulbound rune:
That being the case, if you encounter a rune created by a different player which is soulbound it will have a gray ankh:
Following combinations are possible:
Daily Reward Runes
Daily reward runes are runes purchasable with mana points awarded daily to all characters upon logging in. Differing from facc-char-conjured spellbound runes, daily reward runes are bound to a specific character rather than the account.