I have no blessings.
reroll your account
or wait a few weeks until a blessing is put back into the reward pool. A blessing spent is a blessing lost.
The Gardens have some maps that gives a single blessing as a reward, but that option is out if you can't even do them.
The only other option atm is to summon a Legendary Hero since they give out a free Blessing of their type.
Some you get from Tempest Trials. You also can get them from completing the Grand Hero quests that ask for blessing teams.