Bless is one of, if not the best defensive and offensive spell. It gets way better if you have party members making attack rolls.
Then as you approach level 12-20 saving throws become way more common, so the floating d4 on every save and attack roll becomes dead useful. I would even upcast this to cover you + the whole party. It seems like not a huge deal, but if you turn one weapon attack into a hit, and can save one party member from taking full damage from a spell, etc you have caused an extra ~10-30 damage, and protected your party from 10-30 damage (or from control spells!)
I’m also a big fan of Word of Recall, Death Ward, Holy Weapon, and Aura of Vitality.
Word of Recall can be very clutch. Especially if your party does not have a Wizard/Sorc with any fast travel spells.
Death Ward can protect squishies.
Holy Weapon can supercharge a fighter ( or monk of your DM let’s you cast this on their unarmed strikes). Definitely fun, and dead useful if someone else is already casting Bless.
Aura of Vitality is essentially ~70 HP you can dole out to your party. That’s basically a short rest at lower levels. I’d use this out of combat.