Cleric does have a lot of pretty mediocre 3rd (Also 4th and 5th) level spells.
Out of the not-so-amazing spells:
Mass Healing Word can be decent. Mostly because it only uses a bonus action and it can be super clutch as it can get multiple downed party members back up.
Animate Dead can be useful. The zombie can threaten enemies making them less likely to simply run towards backline party members, while the skeleton can do decent damage (I'm not sure if they fixed this but you at least used to be able to take its bow and give it to another character to get a neat bow with a 1d10 bonus necrotic damage on its damage rolls)
For the good spells:
Spirit Guardians is very powerful. Especially given the synergies with Radiant damage (Dealing double damage to undead enemies and the Luminous items that proc Radiating Orbs)
Glyph of Warding is also good, essentially Fireball but with optimal damage typing for the enemies you encounter (As well as the option for something like the knockback which can allow you to send a bunch of enemies to their death via a pit/cliff)
The spells that specific Domains get at this level are also decent:
Light Domain gets Fireball which is Fireball. Scores of Wizards and Sorcerers swear by this single spell for good reason.
Trickery Domain gets Fear. Which can trivialize many fights due to the fact that it makes enemies drop their weapons (Thus, if your characters then... Pick them up. You've successfully neutered the enemies offensive capabilities)
Knowledge Domain gets Slow. Which is another potent CC spell that can absolutely cripple enemies.
Tempest Domain gets both Call Lightning and Sleet Storm. The former is simply a powerful AoE damage spell that provides a lot of bang for the buck due to being a Concentration spell allowing you to blast 3d10 damage in an Area every turn for only 1 spell slot. The latter is a decent control tool both for its base effect of disrupting enemy Concentration and creating an ice surface in a massive area. But also due to its synergies with Tempest Domain itself in that when you stop concentrating on it the ice it formed turns into water... Which you can electrify and if your Tempest Cleric electrifies it, it will proc the level 6 Tempest Cleric bonus of knocking back enemies from dealing Lightning damage (Turning it into a huge impassable terrain for enemies)
